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Editor Work2008 Vol. 16, No. S1
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2008, 16(S1): 1-5.
Abstract
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Many soil properties with much fuzzy and uncertainty influence the seabed liquefaction, and the liquefaction mechanism is very complex. In this article, the fuzzy method was used to analyze the seabed liquefaction. The fuzzy comprehensive evaluation model of seabed liquefaction degree was established, and the main parameters that influence liquefaction were analyzed. According to the pore pressure variation during liquefaction, the liquefaction was divided into four degrees. The liquefaction degree of Cheng Dao Sea seabed of Yellow River estuary was evaluated by fuzzy comprehensive method, and the result shows the liquefied state. Under wave of a case of 50 years, the soil at most area ofⅠ district and Ⅱ district don’t liquefy, in Ⅲdistrict most area of soil liquefy, and in Ⅳ district soil liquefy. Finally, the results by fuzzy comprehensive method and simple empirical method compared, the two results are consistent, which shows the fuzzy method is feasible in seabed liquefaction degree evaluation.
Many soil properties with much fuzzy and uncertainty influence the seabed liquefaction, and the liquefaction mechanism is very complex. In this article, the fuzzy method was used to analyze the seabed liquefaction. The fuzzy comprehensive evaluation model of seabed liquefaction degree was established, and the main parameters that influence liquefaction were analyzed. According to the pore pressure variation during liquefaction, the liquefaction was divided into four degrees. The liquefaction degree of Cheng Dao Sea seabed of Yellow River estuary was evaluated by fuzzy comprehensive method, and the result shows the liquefied state. Under wave of a case of 50 years, the soil at most area ofⅠ district and Ⅱ district don’t liquefy, in Ⅲdistrict most area of soil liquefy, and in Ⅳ district soil liquefy. Finally, the results by fuzzy comprehensive method and simple empirical method compared, the two results are consistent, which shows the fuzzy method is feasible in seabed liquefaction degree evaluation.
2008, 16(S1): 6-9.
In the foundation of massive area examination and the indoor laboratory static mechanics triaxial tests, choosed the appropriate soil body elastoplasticity modeling according to the serviceability and the usability, and established the macroscopic numerical model of the soft soil of Liaoning Province coastal zone, summarized the influence of different burying depth, the level thick to the location project nature, seeked the rule of region soft soil subsidence. It was validated the established earth statics model by the axial symmetry question's radial direction draining concretion test and undraining concretion test and choosed reasonable subsidence computational method compare with conventional av1-2, e-lgp and so on standard method and definited the subsidence empirical coefficient Ψs of this area for estimate subsidence. Based on contrast of three kind of model computation and the triaxial test, we have obtained the region soft soil practical modellings, the Yingkou-iaobin economic zone usesd nonlinear elastic (Duncan and Chang )model to be more appropriately and the modified Cam-Clay model to be more accurately to Donggang-Langtou.
In the foundation of massive area examination and the indoor laboratory static mechanics triaxial tests, choosed the appropriate soil body elastoplasticity modeling according to the serviceability and the usability, and established the macroscopic numerical model of the soft soil of Liaoning Province coastal zone, summarized the influence of different burying depth, the level thick to the location project nature, seeked the rule of region soft soil subsidence. It was validated the established earth statics model by the axial symmetry question's radial direction draining concretion test and undraining concretion test and choosed reasonable subsidence computational method compare with conventional av1-2, e-lgp and so on standard method and definited the subsidence empirical coefficient Ψs of this area for estimate subsidence. Based on contrast of three kind of model computation and the triaxial test, we have obtained the region soft soil practical modellings, the Yingkou-iaobin economic zone usesd nonlinear elastic (Duncan and Chang )model to be more appropriately and the modified Cam-Clay model to be more accurately to Donggang-Langtou.
2008, 16(S1): 10-14.
According to the monitoring data, the settlement regularities of the existing Lingni seawall were analyzed. Furthermore, the total settlement and the residual settlement after widening engineering by two different embankment fillings, and the differential settlement between the existing seawall and the one to be widened were calculated and compared; the deformation regularities of the seawall after widening were figured out, which proffered the primary design and execution reference for the widening engineering of Lingni seawall.
According to the monitoring data, the settlement regularities of the existing Lingni seawall were analyzed. Furthermore, the total settlement and the residual settlement after widening engineering by two different embankment fillings, and the differential settlement between the existing seawall and the one to be widened were calculated and compared; the deformation regularities of the seawall after widening were figured out, which proffered the primary design and execution reference for the widening engineering of Lingni seawall.
2008, 16(S1): 15-22.
It was a big project that the marine reclamation land project at southeast Xiamen Xinyang bridge .And the area of it was 0.3564 million square meters. It cost 18 months to finish the processes that was enclosing sea, hydraulic fill and foundation treatment. But the processes, which was from researching the treatment to soft foundation to applying the method in site, just cost 6 months. Based on the geological condition, The different dynamic consolidation by drainage method were applied to treat foundation .The effect was fit the design requirements well.
It was a big project that the marine reclamation land project at southeast Xiamen Xinyang bridge .And the area of it was 0.3564 million square meters. It cost 18 months to finish the processes that was enclosing sea, hydraulic fill and foundation treatment. But the processes, which was from researching the treatment to soft foundation to applying the method in site, just cost 6 months. Based on the geological condition, The different dynamic consolidation by drainage method were applied to treat foundation .The effect was fit the design requirements well.
2008, 16(S1): 23-28.
Based on foundation treatment engineering for saturation soft soil of Fujian zone, Vacuum-Preloading-Dynamic Compaction Method was put forward. It fulfiled require of settlement and bearing capacity, Through foundation settlement observation, change of water content, void ratio, compression modulus, Ps value and shear vane test strength of silt soil in treatment fore and aft, farther sum-up relationship between water content and modify coefficient of settlement, practice proved remarkable reference value of engineering practice.
Based on foundation treatment engineering for saturation soft soil of Fujian zone, Vacuum-Preloading-Dynamic Compaction Method was put forward. It fulfiled require of settlement and bearing capacity, Through foundation settlement observation, change of water content, void ratio, compression modulus, Ps value and shear vane test strength of silt soil in treatment fore and aft, farther sum-up relationship between water content and modify coefficient of settlement, practice proved remarkable reference value of engineering practice.
2008, 16(S1): 29-32.
A comprehensive method was applied to analyze a special soil,which was displayed fine soil features but composed of sand soil .In the method crude group volume content was applied to judge whether crude group is the frame of the whole . And the thoughts to correct water content was applied. The method was described through a project example.
A comprehensive method was applied to analyze a special soil,which was displayed fine soil features but composed of sand soil .In the method crude group volume content was applied to judge whether crude group is the frame of the whole . And the thoughts to correct water content was applied. The method was described through a project example.
2008, 16(S1): 33-37.
Hard crust, usually called monolithic sand, exists in the shallow stratum at the Yellow River subaqueous delta. There are two possible explanation mechanics for the formation of monolithic sand: one explanation is that the monolithic sand formats during the sediments depositing process, while the other is that hydrodynamic forces such as waves make the deposited sediments transform into monolithic sand. In the paper, we exerted cycle vibration loading on the inter-tidal mudflat and measured the sediment strength after the test; the data shows that after some stewing time the sediment strength is higher than that before vibration. And in the flume experiments on a silt bed in lab, it is found that some low-strength area vibrates with wave shearing action, which leads to a moisture content depression and a density increase. Our analysis indicates that the monolithic sand at the Yellow River subaqueous delta comes into being in this way: while large waves come, the shallow stratum sediments strength gets depressing until it comes below the shear stress exerted by waves, and then the shallow stratum sediments begin to oscillate with waves, when the waves get smaller or perish, the sediments get stewed and the density and strength increase, and then the monolithic sand shows up.
Hard crust, usually called monolithic sand, exists in the shallow stratum at the Yellow River subaqueous delta. There are two possible explanation mechanics for the formation of monolithic sand: one explanation is that the monolithic sand formats during the sediments depositing process, while the other is that hydrodynamic forces such as waves make the deposited sediments transform into monolithic sand. In the paper, we exerted cycle vibration loading on the inter-tidal mudflat and measured the sediment strength after the test; the data shows that after some stewing time the sediment strength is higher than that before vibration. And in the flume experiments on a silt bed in lab, it is found that some low-strength area vibrates with wave shearing action, which leads to a moisture content depression and a density increase. Our analysis indicates that the monolithic sand at the Yellow River subaqueous delta comes into being in this way: while large waves come, the shallow stratum sediments strength gets depressing until it comes below the shear stress exerted by waves, and then the shallow stratum sediments begin to oscillate with waves, when the waves get smaller or perish, the sediments get stewed and the density and strength increase, and then the monolithic sand shows up.
2008, 16(S1): 38-43.
The cycle stress ratio is the ratio of dynamic strength and soil static strength, as it passes the critical cycle stress ratio,accumulated deformation takes on and soil strength declines.According to researches about the Yellow River Delta, on the Yellow River Subaqueous Delta, the soil strength distribution is not homogeneous, so the critical cycle stress ratio of superficial soil is different. In the action of the storm wave load, the low strength soil, which passes critical cycle stress ratio, would be weaker and the high strength soil could keep stable. The flume experiment shows that the low strength soil in the action of wave shearing force would slide, as the result, strong erosion happens on the bottom. In conclusion, low strength soil is weaker in the action of storm waves, slide in the action of wave shear force and is took away by the bottom current. Then,Local defferential erosion Geomorphology appears on the Yellow River Subaqueous Delta.
The cycle stress ratio is the ratio of dynamic strength and soil static strength, as it passes the critical cycle stress ratio,accumulated deformation takes on and soil strength declines.According to researches about the Yellow River Delta, on the Yellow River Subaqueous Delta, the soil strength distribution is not homogeneous, so the critical cycle stress ratio of superficial soil is different. In the action of the storm wave load, the low strength soil, which passes critical cycle stress ratio, would be weaker and the high strength soil could keep stable. The flume experiment shows that the low strength soil in the action of wave shearing force would slide, as the result, strong erosion happens on the bottom. In conclusion, low strength soil is weaker in the action of storm waves, slide in the action of wave shear force and is took away by the bottom current. Then,Local defferential erosion Geomorphology appears on the Yellow River Subaqueous Delta.
2008, 16(S1): 44-53.
The engineering geological environment of Chengdao in Yellow River delta is very complicated. Along with the development of oil field exploitation, it has great significance to analyse the engineering geological environmental characteristics of Chengdao. The data of bathymetry and topography, 130 boreholes, 37 flow measuring spots and wave elements of different water depth and recurrence interval of Chengdao were collected. The engineering geological environmental zoning of Chengdao was done based on analyzing bathymetry and topography, sediment distribution, physical and mechanical properties of submarine soil and marine hydrodynamics. Moreover, liquefaction of Chengdao zoning induced by wave was calculated using linear wave theory and finite element method to solve the Biot consolidation equation. The results show that the liquefaction of each zone is different mostly because of the different soil properties. And the causes of formation of geological hazard is discussed combining with wave and tide. The systematic analysis and evaluation of the engineering geological environmental characteristics and liquefaction induced by wave is helpful for engineering geological survey and foundation design of Chengdao.
The engineering geological environment of Chengdao in Yellow River delta is very complicated. Along with the development of oil field exploitation, it has great significance to analyse the engineering geological environmental characteristics of Chengdao. The data of bathymetry and topography, 130 boreholes, 37 flow measuring spots and wave elements of different water depth and recurrence interval of Chengdao were collected. The engineering geological environmental zoning of Chengdao was done based on analyzing bathymetry and topography, sediment distribution, physical and mechanical properties of submarine soil and marine hydrodynamics. Moreover, liquefaction of Chengdao zoning induced by wave was calculated using linear wave theory and finite element method to solve the Biot consolidation equation. The results show that the liquefaction of each zone is different mostly because of the different soil properties. And the causes of formation of geological hazard is discussed combining with wave and tide. The systematic analysis and evaluation of the engineering geological environmental characteristics and liquefaction induced by wave is helpful for engineering geological survey and foundation design of Chengdao.
2008, 16(S1): 54-60.
Response frequency and response stress of soil around No.2 subway subway tunnel are monitored when the No.2 subway train transit the tunnel. Cycle triaxial test of saturated soft clay around the No.2 subway tunnel is conducted using the data-monitored. Characteristic of deformation of sasturated soft clay due to subway travelling load is analyzed.The results show that when the No.2 subway train begin to run, small and vertical rebound first occurs in the saturated soft clay in the side wall of tunnel. Although larger deformation don't occur in the saturated soft clay at the side wall of tunnel when No.2 subway train run within period of time, but with the process of time, considerable and asymmetrical subsicence will still occurs.Vertical rebound is transitory and plastic deformation occurs immediately in saturated soft clay in the bottom of tunnel, the larger deformation will occur and the deformation of saturated soft clay in the bottom of tunnel is 30 times than that of saturated soft clay in the side wall of tunnel.
Response frequency and response stress of soil around No.2 subway subway tunnel are monitored when the No.2 subway train transit the tunnel. Cycle triaxial test of saturated soft clay around the No.2 subway tunnel is conducted using the data-monitored. Characteristic of deformation of sasturated soft clay due to subway travelling load is analyzed.The results show that when the No.2 subway train begin to run, small and vertical rebound first occurs in the saturated soft clay in the side wall of tunnel. Although larger deformation don't occur in the saturated soft clay at the side wall of tunnel when No.2 subway train run within period of time, but with the process of time, considerable and asymmetrical subsicence will still occurs.Vertical rebound is transitory and plastic deformation occurs immediately in saturated soft clay in the bottom of tunnel, the larger deformation will occur and the deformation of saturated soft clay in the bottom of tunnel is 30 times than that of saturated soft clay in the side wall of tunnel.
2008, 16(S1): 61-68.
Now the exploitation velocity of underground space is increasing day and day, and the geological hazard problem produced by that appeared gradually. This paper firstly described the geological background of central city zone, then analyzed the geoenvironmental poblem produced during construction of underground project and usable feasibility. These problems include shifting sand conduced by sand and silty soil, and water inrushing of foundation pit conduced by underground water, and soft soil foundation deformation problem, and soil layer variational problem. Finally this paper advanced corresponding prevention countermeasure, which provided reference for plan and construction of underground space.
Now the exploitation velocity of underground space is increasing day and day, and the geological hazard problem produced by that appeared gradually. This paper firstly described the geological background of central city zone, then analyzed the geoenvironmental poblem produced during construction of underground project and usable feasibility. These problems include shifting sand conduced by sand and silty soil, and water inrushing of foundation pit conduced by underground water, and soft soil foundation deformation problem, and soil layer variational problem. Finally this paper advanced corresponding prevention countermeasure, which provided reference for plan and construction of underground space.
2008, 16(S1): 69-72.
China strategic oil reserves will be mainly adopted of underground storage in the future. Groundwater can play a role in sealing the reservoir environment; sometimes it is necessary to be set up water curtain as assistant. Excessive water seepage of underground will bring about adverse effects to construction and to increase costs during the operation. It is very important for storage construction and the safe and reliable operation to establish feasible scheme of groundwater utility and treatment base on rock and groundwater conditions.
China strategic oil reserves will be mainly adopted of underground storage in the future. Groundwater can play a role in sealing the reservoir environment; sometimes it is necessary to be set up water curtain as assistant. Excessive water seepage of underground will bring about adverse effects to construction and to increase costs during the operation. It is very important for storage construction and the safe and reliable operation to establish feasible scheme of groundwater utility and treatment base on rock and groundwater conditions.
2008, 16(S1): 73-77.
The chemical grouting is one of effective methods to treat mine quicksand in difficult grouting strata with low grouting pressure. The research ideas and key questions are proposed in this paper, they are as follows: simulation tests, in-situ monitoring and theoretical analysis will be adopted to study the characteristics of the field of seepage, chemistry and temperature in the coupled action between grouts and quicksand during the treatment of the quicksand hazards. The engineering geological model is established for the cause and treatment to realize the mechanism of fracture, spreading and seepage grouting of chemical grouts in various water-bearing sand layers with different engineering geological behaviors. The modern transducer and information collection techniques can be used in the monitoring of grout pressure, grout volume and grout spreading in whole cause of grouting. The micro mechanism of grout spreading will be studied and micro inspects method for grouting effect will be developed. The research will lay a foundation for prediction and treatment of the serious accident of mine quicksand.
The chemical grouting is one of effective methods to treat mine quicksand in difficult grouting strata with low grouting pressure. The research ideas and key questions are proposed in this paper, they are as follows: simulation tests, in-situ monitoring and theoretical analysis will be adopted to study the characteristics of the field of seepage, chemistry and temperature in the coupled action between grouts and quicksand during the treatment of the quicksand hazards. The engineering geological model is established for the cause and treatment to realize the mechanism of fracture, spreading and seepage grouting of chemical grouts in various water-bearing sand layers with different engineering geological behaviors. The modern transducer and information collection techniques can be used in the monitoring of grout pressure, grout volume and grout spreading in whole cause of grouting. The micro mechanism of grout spreading will be studied and micro inspects method for grouting effect will be developed. The research will lay a foundation for prediction and treatment of the serious accident of mine quicksand.
2008, 16(S1): 78-82.
According to hydrology geology and engineering geology reconnaissance material of this tunnel, its rock layer including the water-rock group's division, the geological water-storing structure, the surface water growth, the ground water growth, the surface water and the ground water military supplies, the tunnel elevation and the appearing spring elevation relations were analyzed and appraised ; the tunnel various spots welled up the water situation was forecasted, and the runoff modulus law was used to forecast the tunnel welled up normally the water volume and wells up most greatly the water volume, the result was forecasted to indicate that the tunnel welled up the water spot mainly to concentrate in middle, welled up normally the water volume 10.3?104m3穌-1, rainy season most greatly welled up water volume 22.9?104m3穌-1, then the tunnel construction proposal was put forward.
According to hydrology geology and engineering geology reconnaissance material of this tunnel, its rock layer including the water-rock group's division, the geological water-storing structure, the surface water growth, the ground water growth, the surface water and the ground water military supplies, the tunnel elevation and the appearing spring elevation relations were analyzed and appraised ; the tunnel various spots welled up the water situation was forecasted, and the runoff modulus law was used to forecast the tunnel welled up normally the water volume and wells up most greatly the water volume, the result was forecasted to indicate that the tunnel welled up the water spot mainly to concentrate in middle, welled up normally the water volume 10.3?104m3穌-1, rainy season most greatly welled up water volume 22.9?104m3穌-1, then the tunnel construction proposal was put forward.
2008, 16(S1): 83-87.
The hydraulic fracturing technology is adopted to define the in-situ stress in the a region where will be build a underground water-sealed oil storage. The measurement result show that the maximum horizontal principal stress is about 10.0 MPa and the minor horizontal principal stress is about 6.0 MPa in the cavern depth. The possibility of the rockburst is analyzed by the Project Rock Mass Classification Criterion, Norway Barton criterion, Houfaliang criterion and the Hoek criterion. The result indicated after the underground cavern excavated, will not have the rock burst phenomenon as a result of the project perturbation. In view of present is unable to obtain the analytic solution of the redistributed stress surrounding the complex cavern, and to precisely judge the possibility of the rockburst in the excavation, the FLAC2D is used to simulate the process of the excavation and obtain the characteristic of the redistributed stress. The result indicated that extremely easy to produce the stress concentration region in some to have the rock burst phenomenon, even medium rock burst by the correction of the Barton rule, which indicate the typical rockburst rule is good at the rockburst possibility in the whole cavern, but not fit to the local cavern.
The hydraulic fracturing technology is adopted to define the in-situ stress in the a region where will be build a underground water-sealed oil storage. The measurement result show that the maximum horizontal principal stress is about 10.0 MPa and the minor horizontal principal stress is about 6.0 MPa in the cavern depth. The possibility of the rockburst is analyzed by the Project Rock Mass Classification Criterion, Norway Barton criterion, Houfaliang criterion and the Hoek criterion. The result indicated after the underground cavern excavated, will not have the rock burst phenomenon as a result of the project perturbation. In view of present is unable to obtain the analytic solution of the redistributed stress surrounding the complex cavern, and to precisely judge the possibility of the rockburst in the excavation, the FLAC2D is used to simulate the process of the excavation and obtain the characteristic of the redistributed stress. The result indicated that extremely easy to produce the stress concentration region in some to have the rock burst phenomenon, even medium rock burst by the correction of the Barton rule, which indicate the typical rockburst rule is good at the rockburst possibility in the whole cavern, but not fit to the local cavern.
2008, 16(S1): 88-92.
Deformation-failure of overburden strata of overlapping mining is more complex than caving of monolayer. On the purpose of getting the development law, the authors work through the overburden strata geological characteristics with analysis of well-measured and drilling television, simulate the deformation-failure of roof overlapping face with discrete element model. And we can obtain the laws of deformation-failure of overburden strata of overlapping mining, which can effectively guide coal mining roof prevention and control work. Of overlapping mining.
Deformation-failure of overburden strata of overlapping mining is more complex than caving of monolayer. On the purpose of getting the development law, the authors work through the overburden strata geological characteristics with analysis of well-measured and drilling television, simulate the deformation-failure of roof overlapping face with discrete element model. And we can obtain the laws of deformation-failure of overburden strata of overlapping mining, which can effectively guide coal mining roof prevention and control work. Of overlapping mining.
2008, 16(S1): 93-97.
A hydraulic engineering project of a city in the northwest of China is taken as an example in the paper. It made three calculating models for the rockmass types which had been named as rock mass Ⅲ、Ⅳ and Ⅴ and it adopted 2D-elastic-plastic finite element method to simulate the stability of surrounding rockmass in low ground stress region. The simulated result shows that deformation and failure zones would be formed at the arch and both sides of excavation, but the failure zones formed at the arch of excavation are especially more serious than those at both sides.The achievement of this research will play a very important role in making progress in underground engineering projects.
A hydraulic engineering project of a city in the northwest of China is taken as an example in the paper. It made three calculating models for the rockmass types which had been named as rock mass Ⅲ、Ⅳ and Ⅴ and it adopted 2D-elastic-plastic finite element method to simulate the stability of surrounding rockmass in low ground stress region. The simulated result shows that deformation and failure zones would be formed at the arch and both sides of excavation, but the failure zones formed at the arch of excavation are especially more serious than those at both sides.The achievement of this research will play a very important role in making progress in underground engineering projects.
2008, 16(S1): 98-102.
The main engineering geotechnical problems were the existence of rocks and soft soil in the shallow entrance, the two lager faults, karst and karst water, and gas in Tanchang tunnel. The four main issues focused on the entrance of the tunnel, which made the tunnel construction difficult and the risk increased greatly. Analysis of these issues was done in detail, the comprehensive geological prediction technology in construction period and the corresponding contingency plans for construction were proposed. By the geological prediction of construction period and the implementation of the tunnel excavation verification, the tunnel project construction was done safety under the guidance, complex engineering geological problems of the tunnel were solved and the construction quality was protected.
The main engineering geotechnical problems were the existence of rocks and soft soil in the shallow entrance, the two lager faults, karst and karst water, and gas in Tanchang tunnel. The four main issues focused on the entrance of the tunnel, which made the tunnel construction difficult and the risk increased greatly. Analysis of these issues was done in detail, the comprehensive geological prediction technology in construction period and the corresponding contingency plans for construction were proposed. By the geological prediction of construction period and the implementation of the tunnel excavation verification, the tunnel project construction was done safety under the guidance, complex engineering geological problems of the tunnel were solved and the construction quality was protected.
2008, 16(S1): 103-107.
According to the main problems of domestic and international highway tunnel project construction quality, construction quality management technology was discussed in detail, with the actual situation of some tunnel constructed in Guizhou Province in recent years. One, geological conditions and geological problems should be analysis in detail. Two, a targeted Geological Forecast method should be chose to imply comprehensive geological forecast. Different construction measures were suggested according to monitoring measurement data and different geological problems exposed in tunnel construction. To protect the quality of construction, quality tests of advance and initial support system should be done in target. Comprehensive quality testing should be done after all construction projects completed. As analysis, tunnel construction quality management was a system, which needs a variety ways combined with point and plane, with qualitative and quantitative, with macro control and subtle management. Thus highway tunnel project construction quality and management technology could be upgraded to a new height.
According to the main problems of domestic and international highway tunnel project construction quality, construction quality management technology was discussed in detail, with the actual situation of some tunnel constructed in Guizhou Province in recent years. One, geological conditions and geological problems should be analysis in detail. Two, a targeted Geological Forecast method should be chose to imply comprehensive geological forecast. Different construction measures were suggested according to monitoring measurement data and different geological problems exposed in tunnel construction. To protect the quality of construction, quality tests of advance and initial support system should be done in target. Comprehensive quality testing should be done after all construction projects completed. As analysis, tunnel construction quality management was a system, which needs a variety ways combined with point and plane, with qualitative and quantitative, with macro control and subtle management. Thus highway tunnel project construction quality and management technology could be upgraded to a new height.
FINITE ELEMENT ANALYSIS ON EFFECT OF BIG SHIELD CONSTRUCTION UNDER SHALLOW SOIL AROUND THE BUILDINGS
2008, 16(S1): 108-110.
Big shield Construction under shallow soil will inevitably effect the buildings around. Finite element analysis will be used in this article, calculate the vertical and horizontal displacement, to simulate the effect in the project of Waitan Tunnel, Shanghai.
Big shield Construction under shallow soil will inevitably effect the buildings around. Finite element analysis will be used in this article, calculate the vertical and horizontal displacement, to simulate the effect in the project of Waitan Tunnel, Shanghai.
2008, 16(S1): 111-115.
According to the situation that general tunnel geology prediction methods were used to TBM wery difficult, combined with the advantages and disadvantages of other methods to TBM construction, and with their application, the study on effective HSP geology prediction technology was developed to fit for TBM construction. the signal of TBM boring machine cutters cutting rocks was used as the Excitation signal of HSP Acoustic Reflection Geological Prediction. Also several geology prediction field tests were done. Practice proved that it was successful in Dahuofang hydraulic tunnel project by using the technology geology prediction for TBM construction. The geology prediction of TBM construction was carried out under the conditions without the TBM stop-waiting, which was positive to guiding TBM construction.
According to the situation that general tunnel geology prediction methods were used to TBM wery difficult, combined with the advantages and disadvantages of other methods to TBM construction, and with their application, the study on effective HSP geology prediction technology was developed to fit for TBM construction. the signal of TBM boring machine cutters cutting rocks was used as the Excitation signal of HSP Acoustic Reflection Geological Prediction. Also several geology prediction field tests were done. Practice proved that it was successful in Dahuofang hydraulic tunnel project by using the technology geology prediction for TBM construction. The geology prediction of TBM construction was carried out under the conditions without the TBM stop-waiting, which was positive to guiding TBM construction.
2008, 16(S1): 116-120.
Highway tunnel construction monitoring is important role in the information-oriented construction. It's also the basic requirement of the NATM. In this paper, monitored some typical cross-section of the large span anti-arch tunnel in Wen Zhou ring expressway north section. And do some comparative analysis with the numerical simulation.
Highway tunnel construction monitoring is important role in the information-oriented construction. It's also the basic requirement of the NATM. In this paper, monitored some typical cross-section of the large span anti-arch tunnel in Wen Zhou ring expressway north section. And do some comparative analysis with the numerical simulation.
2008, 16(S1): 121-123.
This thesis documents a method to calculate deviation of tunnel line. It is based on tunnel line's character to analyse different linestyle, relize a batch of tunnel line's 3-D coordinate quick calculation. This supply a way for definiteness of tunnel line's deviation during shield construction and monitor of centre coordinate excursion after ring plate's assembly. Engineering practices prove this method measure precision can achieve ~mm. It provides highly utility value in field calculation as well as later moniter.
This thesis documents a method to calculate deviation of tunnel line. It is based on tunnel line's character to analyse different linestyle, relize a batch of tunnel line's 3-D coordinate quick calculation. This supply a way for definiteness of tunnel line's deviation during shield construction and monitor of centre coordinate excursion after ring plate's assembly. Engineering practices prove this method measure precision can achieve ~mm. It provides highly utility value in field calculation as well as later moniter.
2008, 16(S1): 124-127.
This paper studied the deep diggings of ZhangXiaolou coal mine XuZhou which the distance between coal seams of the research area and floor is over 1200m. On the base of analyzing the macroscopical in-situ stress field, the paper tested the in-situ stress of terranes and the rule that in-site stress transformation following depth was concluded. The paper also put forward a practical method which can be used to preliminarily estimate in-situ stress value in strata.The paper made use of nonlinear finite element program calculating the horizontal section and two vertical section of typical mining level. On this condition, the paper tested and analyzed the energy liability to rock burst of the mostly coal seams. The paper appraised outburst fatalness zone of main coal seam in research area. The content was important to future safety production of the coal mine. Moreover the whole research method had wide guiding significance for other deep coal mine level.
This paper studied the deep diggings of ZhangXiaolou coal mine XuZhou which the distance between coal seams of the research area and floor is over 1200m. On the base of analyzing the macroscopical in-situ stress field, the paper tested the in-situ stress of terranes and the rule that in-site stress transformation following depth was concluded. The paper also put forward a practical method which can be used to preliminarily estimate in-situ stress value in strata.The paper made use of nonlinear finite element program calculating the horizontal section and two vertical section of typical mining level. On this condition, the paper tested and analyzed the energy liability to rock burst of the mostly coal seams. The paper appraised outburst fatalness zone of main coal seam in research area. The content was important to future safety production of the coal mine. Moreover the whole research method had wide guiding significance for other deep coal mine level.
2008, 16(S1): 128-131.
Traditional infiltration control project discards or little discards the occurrence factor of geology structural plane,so it always gets half the result with twice the effort,or it can't apply it's original action.The drainage design of HUILONG pumped-storage power station factory building under ground based on the statistic analysis on the excavation geology material,uses the special program hunting the best direction of boreholl, adjust correspondly the quantities combining hydrogeologic present state.It proves the reinforce design method against the rock mass can achieve marked efficiency, it’s worth to popularize.
Traditional infiltration control project discards or little discards the occurrence factor of geology structural plane,so it always gets half the result with twice the effort,or it can't apply it's original action.The drainage design of HUILONG pumped-storage power station factory building under ground based on the statistic analysis on the excavation geology material,uses the special program hunting the best direction of boreholl, adjust correspondly the quantities combining hydrogeologic present state.It proves the reinforce design method against the rock mass can achieve marked efficiency, it’s worth to popularize.
2008, 16(S1): 132-137.
Landsliding is a physical process involving sliding friction between its slip zone and the moved materials. It has been believed that there is a frictional heat within the slip zone when a rapid, large-scale and deep-seated landslide occurs. Illite is one of the clay minerals most sensitive to temperature that alters illite's crystallinity, and the latter has been widely used as a useful indicator of degree of metamorphism, neotectonic movement, etc. Illite crystallinity was hence used in this paper to be an indicator about a rapid, large-scale and deep-seated landslide's sliding mechanism in terms of fractional heat. By comparison of variation of indices of illite crystallinity of three landslides’ materials, i.e., the landslides at Huangtupo,Tanping and Xietan in the Three Gorges area, it was found that No. 1 slide at Huangtupo landslide, Tanping landslide and Xietan landslide were slow-moving landslides, whereas No.2 slide of Huangtupo landslide may have experienced a rapid sliding process.
Landsliding is a physical process involving sliding friction between its slip zone and the moved materials. It has been believed that there is a frictional heat within the slip zone when a rapid, large-scale and deep-seated landslide occurs. Illite is one of the clay minerals most sensitive to temperature that alters illite's crystallinity, and the latter has been widely used as a useful indicator of degree of metamorphism, neotectonic movement, etc. Illite crystallinity was hence used in this paper to be an indicator about a rapid, large-scale and deep-seated landslide's sliding mechanism in terms of fractional heat. By comparison of variation of indices of illite crystallinity of three landslides’ materials, i.e., the landslides at Huangtupo,Tanping and Xietan in the Three Gorges area, it was found that No. 1 slide at Huangtupo landslide, Tanping landslide and Xietan landslide were slow-moving landslides, whereas No.2 slide of Huangtupo landslide may have experienced a rapid sliding process.
2008, 16(S1): 138-144.
The west to east gas pipeline project is a significant part in our national energy sources stratagem, landslide and mudflow hazards are well developed in Loess area, Jingbian to Yanchuan section, which are potential threaten to the oil-gas pipeline. In the article, Landslide is set as a case study, which is the main kind of geological hazards in this Loess area. Based on multiple remote sensing Information, the energy, distance from the pipeline and stability of the landslides are taken as evaluation indices, the geological hazard evaluation model for oil-gas pipeline in loess area are established, Practice shows that the model is right and useful.
The west to east gas pipeline project is a significant part in our national energy sources stratagem, landslide and mudflow hazards are well developed in Loess area, Jingbian to Yanchuan section, which are potential threaten to the oil-gas pipeline. In the article, Landslide is set as a case study, which is the main kind of geological hazards in this Loess area. Based on multiple remote sensing Information, the energy, distance from the pipeline and stability of the landslides are taken as evaluation indices, the geological hazard evaluation model for oil-gas pipeline in loess area are established, Practice shows that the model is right and useful.
2008, 16(S1): 145-150.
Based upon the investigation of the characteristics of fault systems and analysis for the relationship between the fault systems and landslide, debris flow et al geological hazards in the westen Qingling, the controlling function of fault system for geological hazard development is discussed. It is proposed that fault systems and its activities are essential factors for the development of geological hazards although geological hazards are actually the results of complex and composite actions of interior and exterior dynamic geological processes. The controlling functions of fault system for geological hazard development could be direct or indirect, mainly as follow, (1)the geological hazards generally develop along the faults, which often determines the intensity and spatial distribution of geological hazards; (2) the fractural zone and influence zone of faults often provide mass debris substance and structural slide faces for landslide and mud-debris flow; (3) the fault activities, especially earthquake activity of faults are the important induced factor for geological hazards; (4) fractured rocks and geomorphic height contrasts for the prolonged activity of faults provide the favorite conditions for water corrosion, which would develop the slope geomorphic condition for geological hazards. Therefore in studying landslide and mud-debris flow, we should put them under the regional geological background, especially regional fault framework, fault zone structural features and fault activities, to understand its development..
Based upon the investigation of the characteristics of fault systems and analysis for the relationship between the fault systems and landslide, debris flow et al geological hazards in the westen Qingling, the controlling function of fault system for geological hazard development is discussed. It is proposed that fault systems and its activities are essential factors for the development of geological hazards although geological hazards are actually the results of complex and composite actions of interior and exterior dynamic geological processes. The controlling functions of fault system for geological hazard development could be direct or indirect, mainly as follow, (1)the geological hazards generally develop along the faults, which often determines the intensity and spatial distribution of geological hazards; (2) the fractural zone and influence zone of faults often provide mass debris substance and structural slide faces for landslide and mud-debris flow; (3) the fault activities, especially earthquake activity of faults are the important induced factor for geological hazards; (4) fractured rocks and geomorphic height contrasts for the prolonged activity of faults provide the favorite conditions for water corrosion, which would develop the slope geomorphic condition for geological hazards. Therefore in studying landslide and mud-debris flow, we should put them under the regional geological background, especially regional fault framework, fault zone structural features and fault activities, to understand its development..
2008, 16(S1): 151-154.
The main cause of soil mass deformation and subsidence derives from the drawdown by continuous over exploitation of deep groundwater, which has made a combined depression cone with adjacent cities base on studies on the seepage deformation of clayey soil. The paper takes HeBei Province as an example to show that the overexploitation of deep groundwater may cause issues of subsidence and ground fissures. These disasters are developing and producing a severity impact for people daily life. The effective measures should be considered that the local government takes action to control the exploitation of deep groundwater within an allowable extent. This is the key measure to prevent geological environment hazards.
The main cause of soil mass deformation and subsidence derives from the drawdown by continuous over exploitation of deep groundwater, which has made a combined depression cone with adjacent cities base on studies on the seepage deformation of clayey soil. The paper takes HeBei Province as an example to show that the overexploitation of deep groundwater may cause issues of subsidence and ground fissures. These disasters are developing and producing a severity impact for people daily life. The effective measures should be considered that the local government takes action to control the exploitation of deep groundwater within an allowable extent. This is the key measure to prevent geological environment hazards.
2008, 16(S1): 155-160.
Regional geological background of talus along Shuifu-Maliuwan high way in Yunnan province was generalized by on-site research. The developmental properties of these talus were analyzed considering their geometric shape, material composition and forming condition, while new methods of talus classification by planal configuration, longitudinal and cross sectional morphology were presented, the talus structure was classified according to its composition and contact condition between its inner particles. Based on field investigation on talus’s developmental features and diseases, the theses also analyzed its instability mechanism and the hazard to roadbed, bridge and tunnel engineering caused by the talus during Shuifu-Maliuwan highway project . This thesis can be used as reference for geologic hazard control induced by talus during engineering construction.
Regional geological background of talus along Shuifu-Maliuwan high way in Yunnan province was generalized by on-site research. The developmental properties of these talus were analyzed considering their geometric shape, material composition and forming condition, while new methods of talus classification by planal configuration, longitudinal and cross sectional morphology were presented, the talus structure was classified according to its composition and contact condition between its inner particles. Based on field investigation on talus’s developmental features and diseases, the theses also analyzed its instability mechanism and the hazard to roadbed, bridge and tunnel engineering caused by the talus during Shuifu-Maliuwan highway project . This thesis can be used as reference for geologic hazard control induced by talus during engineering construction.
2008, 16(S1): 161-163.
There are great differences between over consolidated soil and normally consolidated soil in compression deformation characteristics. In this paper, the author analyzes the trait of plate loading test curve of over consolidation soil. Two methods were proposed to confirm the bearing capacity in according to the plate loading test curve of over consolidated soil, which has much significance for engineering.
There are great differences between over consolidated soil and normally consolidated soil in compression deformation characteristics. In this paper, the author analyzes the trait of plate loading test curve of over consolidation soil. Two methods were proposed to confirm the bearing capacity in according to the plate loading test curve of over consolidated soil, which has much significance for engineering.
2008, 16(S1): 164-168.
The Liaoning Province southeast area is vast in territory, the natural environment is superior, good communications. However, as in recent years human engineering and the worsening economic activities, natural environment has been seriously damaged, has serious geological disaster situation, people's lives and property and to the economic construction and greatly harm huge losses. This paper focus on geological disasters in a disaster, the progressive layers, interrelated, a multi-level system of geological disasters in disaster assessment. Through geological hazards assessment, a comprehensive understanding of geological disasters in the disaster area of planning for the development of regional disaster reduction, disaster prevention works as well as the deployment of regional land improvement and development resources provide the basic data.
The Liaoning Province southeast area is vast in territory, the natural environment is superior, good communications. However, as in recent years human engineering and the worsening economic activities, natural environment has been seriously damaged, has serious geological disaster situation, people's lives and property and to the economic construction and greatly harm huge losses. This paper focus on geological disasters in a disaster, the progressive layers, interrelated, a multi-level system of geological disasters in disaster assessment. Through geological hazards assessment, a comprehensive understanding of geological disasters in the disaster area of planning for the development of regional disaster reduction, disaster prevention works as well as the deployment of regional land improvement and development resources provide the basic data.
2008, 16(S1): 169-173.
Engineering geological evaluation of the environmental quality is extremely important in the planning and construction in the city. Based in Beijing Metro Planning Tongzhou construction site suitability evaluation, this paper describes clustering analysis and evaluation methods, establishes a set of indicators, and provides a quantitative evaluation of the theoretical basis for evaluation for the future of the engineering geological conditions.
Engineering geological evaluation of the environmental quality is extremely important in the planning and construction in the city. Based in Beijing Metro Planning Tongzhou construction site suitability evaluation, this paper describes clustering analysis and evaluation methods, establishes a set of indicators, and provides a quantitative evaluation of the theoretical basis for evaluation for the future of the engineering geological conditions.
2008, 16(S1): 174-181.
According to many deep researches and to the latest information of this area about its geology, its earth structure; by using the physique of the deep earth, the history of the earthquake and the study of the tradition architectures, we obtain the result that this area is very instable. It happened here and areas nearby some big earthquakes around 7.5 degree. There is a threat that an earthquake more than 7 degrees would take place recently. What's more, the Intensity of earthquake here is more than 9degree which raises even more the danger.
According to many deep researches and to the latest information of this area about its geology, its earth structure; by using the physique of the deep earth, the history of the earthquake and the study of the tradition architectures, we obtain the result that this area is very instable. It happened here and areas nearby some big earthquakes around 7.5 degree. There is a threat that an earthquake more than 7 degrees would take place recently. What's more, the Intensity of earthquake here is more than 9degree which raises even more the danger.
2008, 16(S1): 182-187.
According to the main problems of Leshan Buddha and the surrounding environment, based on the analysis of the regional engineering geological conditions, design planning of environment and engineering geological conditions were proposed of Buddha body, Buddha feet's, dangerous rock of Zaijiuting, front door and Buddha plank road for protection. Part of the project had been implemented ]and the effect was satisfied, which were being validated in time.
According to the main problems of Leshan Buddha and the surrounding environment, based on the analysis of the regional engineering geological conditions, design planning of environment and engineering geological conditions were proposed of Buddha body, Buddha feet's, dangerous rock of Zaijiuting, front door and Buddha plank road for protection. Part of the project had been implemented ]and the effect was satisfied, which were being validated in time.
2008, 16(S1): 188-192.
Applied remote sensing method in studying the physical geographic condition, the rock properties and tectonic of Jiulonghe river valley in Yunnan province, the paper has established appropriate remote sensing signs. Based on these, according to the synthetically study content of hydro-geology, the paper has made the interpretation indications of hydro-geological factors remote sensing image and studied the characteristics of hydro-geological remote sensing image.
Applied remote sensing method in studying the physical geographic condition, the rock properties and tectonic of Jiulonghe river valley in Yunnan province, the paper has established appropriate remote sensing signs. Based on these, according to the synthetically study content of hydro-geology, the paper has made the interpretation indications of hydro-geological factors remote sensing image and studied the characteristics of hydro-geological remote sensing image.
2008, 16(S1): 193-196.
The evolution of the water film in saturated sands and the responses of pore water and skeleton are investigated. It is shown that if the sand layer loses its strength and is not choked, there is no stable water film. If the choking state may keep, the water film may expand gradually, otherwise, water film will expand first and then enclose. Pore water's velocity, grain's velocity and pore pressure have discontinues at the first stage of choking. Discontinues will disappear with the disappearing of choking state.
The evolution of the water film in saturated sands and the responses of pore water and skeleton are investigated. It is shown that if the sand layer loses its strength and is not choked, there is no stable water film. If the choking state may keep, the water film may expand gradually, otherwise, water film will expand first and then enclose. Pore water's velocity, grain's velocity and pore pressure have discontinues at the first stage of choking. Discontinues will disappear with the disappearing of choking state.
2008, 16(S1): 197-201.
The paper studies the problem of a slope stability under the condition of before applying load and after applying load .The problem is analyzed and computed under the condition of applying cooling tower load by using finite element method and Mohr-Coulomb yielding criterion .From the result obtained we draw some conclusions: The stability of whole slope is mainly related to the deformation stability; The existence of columnar joint has adverse effect to the slope stability; The stability of slope is influenced by the cooling tower; The deformation of slope is enhanced with the growth of time; The main damage form of slope is toppling.
The paper studies the problem of a slope stability under the condition of before applying load and after applying load .The problem is analyzed and computed under the condition of applying cooling tower load by using finite element method and Mohr-Coulomb yielding criterion .From the result obtained we draw some conclusions: The stability of whole slope is mainly related to the deformation stability; The existence of columnar joint has adverse effect to the slope stability; The stability of slope is influenced by the cooling tower; The deformation of slope is enhanced with the growth of time; The main damage form of slope is toppling.
2008, 16(S1): 202-207.
One of the difficult technical problems for hydropower development in west China is how to take the undisturbed soil samples from the thick deposits in the river bed through boreholes and how to gained the physical and mechanical properties by the laboratory test and in-situ test. The thickness of the river deposits at the Wudongde dam site area is 52~65m.The alluvial, the colluvium and landslide mass constitute the river deposit. So the component and the structure of the river deposits show inhomogeneous Properties. The Wudongde narrow valley is apt to building the arc dam type. So the stability of the high cofferdam and the slope of the deep foundation pit are prominent engineering geological problems. For exploring the engineering characteristics of the river deposit, the advance exploring technology and the methods of the laboratory test and in-situ test were adopted. The standard penetration test was used during the drilling in order to pre-exploring the soft layer such as silt-clay, clay. In order to taking the undisturbed soil samples from the borehole, Single Rotary and Double Tube Core Barrel and The hammer Double Core Barrel With Inner Tube were developed. In order to verifying the physical and mechanical properties, the in-situ test (including the heavy dynamic penetration test, super-heavy dynamic penetration test, pressuremeter test, pumping test, acoustic prospecting and borehole TV .etc) and the laboratory test, the simulation of the soil sample gradation test were used . It is successfully solved the difficult problems of the exploration and the test in the thick river deposits and provided the reliable parameters for designing the high cofferdam and the cut slope of the deep foundation pit.
One of the difficult technical problems for hydropower development in west China is how to take the undisturbed soil samples from the thick deposits in the river bed through boreholes and how to gained the physical and mechanical properties by the laboratory test and in-situ test. The thickness of the river deposits at the Wudongde dam site area is 52~65m.The alluvial, the colluvium and landslide mass constitute the river deposit. So the component and the structure of the river deposits show inhomogeneous Properties. The Wudongde narrow valley is apt to building the arc dam type. So the stability of the high cofferdam and the slope of the deep foundation pit are prominent engineering geological problems. For exploring the engineering characteristics of the river deposit, the advance exploring technology and the methods of the laboratory test and in-situ test were adopted. The standard penetration test was used during the drilling in order to pre-exploring the soft layer such as silt-clay, clay. In order to taking the undisturbed soil samples from the borehole, Single Rotary and Double Tube Core Barrel and The hammer Double Core Barrel With Inner Tube were developed. In order to verifying the physical and mechanical properties, the in-situ test (including the heavy dynamic penetration test, super-heavy dynamic penetration test, pressuremeter test, pumping test, acoustic prospecting and borehole TV .etc) and the laboratory test, the simulation of the soil sample gradation test were used . It is successfully solved the difficult problems of the exploration and the test in the thick river deposits and provided the reliable parameters for designing the high cofferdam and the cut slope of the deep foundation pit.
2008, 16(S1): 208-211.
The Landslide Geology Fatality has posed serious disadvantages on the safe and development of local socity in Zhejiang province. This article analyses and studys the regularities of distribution and developing pattern of the Landslide Geology Fatality in Zhejiang province based on studying the developing condition and anatomizing the typical types of Landslide Geology Fatality. The results are that the landslide is main geology fatality in Zhejiang province, it has the characteristics of group-development and small size and soil-landslide first and rock-landslide second. The soil-landslide mainly locates at volcaniclastic rock zone in northern and east-northern Zhejiang province; the rock-landslide mainly locates at the sedimentary rock zone in west-northern Zhejiang province. Man-made action and heavy rainfall in flood season are the prime reasons of landslide in Zhejiang province. The heavy rainfall phase is the most likely period of landslide development. This resultes is going to provide the enacting reasonable and effectual countermeasure for calamity with the important environgeology decision-making gists in Zhejiang province.
The Landslide Geology Fatality has posed serious disadvantages on the safe and development of local socity in Zhejiang province. This article analyses and studys the regularities of distribution and developing pattern of the Landslide Geology Fatality in Zhejiang province based on studying the developing condition and anatomizing the typical types of Landslide Geology Fatality. The results are that the landslide is main geology fatality in Zhejiang province, it has the characteristics of group-development and small size and soil-landslide first and rock-landslide second. The soil-landslide mainly locates at volcaniclastic rock zone in northern and east-northern Zhejiang province; the rock-landslide mainly locates at the sedimentary rock zone in west-northern Zhejiang province. Man-made action and heavy rainfall in flood season are the prime reasons of landslide in Zhejiang province. The heavy rainfall phase is the most likely period of landslide development. This resultes is going to provide the enacting reasonable and effectual countermeasure for calamity with the important environgeology decision-making gists in Zhejiang province.
2008, 16(S1): 212-216.
In deep foundation pit, piping and flowing soil are two kinds of seepage deformation, causing many accidents directly. In this paper, the mechanism of seepage deformation is primarily summed up and discussed. Good dewatering is suggested as the main countermeasure to avoid seepage deformation in deep foundation pit, meanwhile, dewatering also proves to be very important to ensure the smooth excavation of deep foundation pit through case history.
In deep foundation pit, piping and flowing soil are two kinds of seepage deformation, causing many accidents directly. In this paper, the mechanism of seepage deformation is primarily summed up and discussed. Good dewatering is suggested as the main countermeasure to avoid seepage deformation in deep foundation pit, meanwhile, dewatering also proves to be very important to ensure the smooth excavation of deep foundation pit through case history.
2008, 16(S1): 217-221.
Dip slope deformation and failure deduced abound shallow rock mass landslides along Duhe river. On the basis the field investigation, the paper described the dip slope deformation and failure phenomenon on natural outcrops, and five stages were recognized as (1) Rheological stage with unloading cranny and rhombus rock mass formed, (2)Rhombus rockmass distortion stage, (3)Bend and break off stage, (4)Transfixiong stage of tensile crack, (5)Shallow deformation and failure stage. The field analysis on the process helps to understand the mechanics of slope deformation and failure and to prompt prevent and cure work on this kind of slope.
Dip slope deformation and failure deduced abound shallow rock mass landslides along Duhe river. On the basis the field investigation, the paper described the dip slope deformation and failure phenomenon on natural outcrops, and five stages were recognized as (1) Rheological stage with unloading cranny and rhombus rock mass formed, (2)Rhombus rockmass distortion stage, (3)Bend and break off stage, (4)Transfixiong stage of tensile crack, (5)Shallow deformation and failure stage. The field analysis on the process helps to understand the mechanics of slope deformation and failure and to prompt prevent and cure work on this kind of slope.
2008, 16(S1): 222-225.
The dams of barrier lakes are usually loose and weak, and they are very likely to fail when subjected to strong aftershocks or heavy rains, which may bring tremendous disasters. This paper analyzes the stability of a barrier lake dam before and after the rise of water table, as well as the dynamic response to an aftershock.
The dams of barrier lakes are usually loose and weak, and they are very likely to fail when subjected to strong aftershocks or heavy rains, which may bring tremendous disasters. This paper analyzes the stability of a barrier lake dam before and after the rise of water table, as well as the dynamic response to an aftershock.
2008, 16(S1): 226-229.
Softrock exists regularly with solidrock by mutual stratum or act as intercalary strata of solidrock in nature. Softrock produce flowing deformation when it is affected by stress which greater than the soften critical load, which will directly affect stabilization of slope. The types of rock in the northeast part of yunnan mainly are sand shale in the Mesozoic group Cretaceous and Jurassic also including the carbonate rocks with marl in Paleozoic. The rocks often occur in the formation of horizontal direction orhorizontal low-angled. Because of crust raising and stream cutting it is easy to form the steep rocky-slope or large rock packing slope (e.g. jinsha valley and guan valley). The damage of the slope mainly results from the rheology of soft rock interlayer under the action of high stress. Slope deformation obeys the laws of soft rock deformation of special structure rock mass, which form deformation from bottom to top, from out to within of the slop, and form large rock accumulate.
Softrock exists regularly with solidrock by mutual stratum or act as intercalary strata of solidrock in nature. Softrock produce flowing deformation when it is affected by stress which greater than the soften critical load, which will directly affect stabilization of slope. The types of rock in the northeast part of yunnan mainly are sand shale in the Mesozoic group Cretaceous and Jurassic also including the carbonate rocks with marl in Paleozoic. The rocks often occur in the formation of horizontal direction orhorizontal low-angled. Because of crust raising and stream cutting it is easy to form the steep rocky-slope or large rock packing slope (e.g. jinsha valley and guan valley). The damage of the slope mainly results from the rheology of soft rock interlayer under the action of high stress. Slope deformation obeys the laws of soft rock deformation of special structure rock mass, which form deformation from bottom to top, from out to within of the slop, and form large rock accumulate.
2008, 16(S1): 230-233.
It is very significant for engineering guide to study on the dynamic compactness to fill foundation in land area. Based on the fact, the parameter and process of dynamic compaction test are defined. The reasonable working technique and working parameter are obtained from the test. The result of stabilization is well acquired according to indices of physical and mechanical properties of soil, SPT, load-settlement testing. The important parameter and scientific basis are provided by study on the testing.
It is very significant for engineering guide to study on the dynamic compactness to fill foundation in land area. Based on the fact, the parameter and process of dynamic compaction test are defined. The reasonable working technique and working parameter are obtained from the test. The result of stabilization is well acquired according to indices of physical and mechanical properties of soil, SPT, load-settlement testing. The important parameter and scientific basis are provided by study on the testing.
2008, 16(S1): 234-236.
As the expressway construction speed accelerating,various problems appeared with it,and the high embankment problem is very important to the safety of highroad traffic .The contribution to high embankment sedimentation formation include filling material,the control of water in construction process,compaction system and so on,accurately predicting the high embankment sedimentation after the project controlled the road construction mode, filling mode and other construction technology .This article made a summarize research condition of the high embankment sedimentation calculation,model and so on.It is important to the research of highroad sedimentation after the project.
As the expressway construction speed accelerating,various problems appeared with it,and the high embankment problem is very important to the safety of highroad traffic .The contribution to high embankment sedimentation formation include filling material,the control of water in construction process,compaction system and so on,accurately predicting the high embankment sedimentation after the project controlled the road construction mode, filling mode and other construction technology .This article made a summarize research condition of the high embankment sedimentation calculation,model and so on.It is important to the research of highroad sedimentation after the project.
2008, 16(S1): 237-241.
It is every important for the deformation control of the bridge pile foundation in the design of bridge with high piers. Based on three dimensions numerical simulation, the stabilizing project about digging cavern pile with the hands is analyzed. In terms of the stimulant result, comparing the both pile foundation show that anchor pile foundation can control effectively the deformation and save investment.
It is every important for the deformation control of the bridge pile foundation in the design of bridge with high piers. Based on three dimensions numerical simulation, the stabilizing project about digging cavern pile with the hands is analyzed. In terms of the stimulant result, comparing the both pile foundation show that anchor pile foundation can control effectively the deformation and save investment.
2008, 16(S1): 242-244.
Mining in Huainan old mineral area and Xinji mineral area is threaten by karstic water of coal seat. They mine by limiting pressure and ascertain a water gushing coefficient. However, we analyzed a great deal of data in Huainan detailedly and have done experiment which imitated scaleboard breakage in mining.And then we found that water gushing coefficient was conservative. The key point is that the consideration of water-resisting layer was conservative.They have considered soft rock under the coal as the water-resisting layer. We considered that soft rock layer and hard rock layer alternating can be considered as relative water-resisting layer. Experimen phenomena have indicated that soft rock layer and hard rock layer alternating can protect each other,and reduce the depth of deformation destruction.
Mining in Huainan old mineral area and Xinji mineral area is threaten by karstic water of coal seat. They mine by limiting pressure and ascertain a water gushing coefficient. However, we analyzed a great deal of data in Huainan detailedly and have done experiment which imitated scaleboard breakage in mining.And then we found that water gushing coefficient was conservative. The key point is that the consideration of water-resisting layer was conservative.They have considered soft rock under the coal as the water-resisting layer. We considered that soft rock layer and hard rock layer alternating can be considered as relative water-resisting layer. Experimen phenomena have indicated that soft rock layer and hard rock layer alternating can protect each other,and reduce the depth of deformation destruction.
2008, 16(S1): 245-250.
Along with gradual advance of transplantation engineering construction for Three Gorges Project, a lot of engineering slopes have been formed in the Three Gorges Reservoir Area, including soil slopes composed of residual soil, slumping mass, earth filling, swelling soil etc., and rock slopes composed of massive, stratiform and cataclastic rock. Different types of engineering slopes have different deformation and failure modes, so different measures such as drainage, flexible protecting net, shotcrete and rock bolt, lattice, retaining wall, anti-slide pile and pile-plank wall should be adopted according to their failure modes in order to assure stability of slopes and get better protection effect.
Along with gradual advance of transplantation engineering construction for Three Gorges Project, a lot of engineering slopes have been formed in the Three Gorges Reservoir Area, including soil slopes composed of residual soil, slumping mass, earth filling, swelling soil etc., and rock slopes composed of massive, stratiform and cataclastic rock. Different types of engineering slopes have different deformation and failure modes, so different measures such as drainage, flexible protecting net, shotcrete and rock bolt, lattice, retaining wall, anti-slide pile and pile-plank wall should be adopted according to their failure modes in order to assure stability of slopes and get better protection effect.
2008, 16(S1): 251-256.
This paper presents new formulas related to limit equilibrium analysis of the vertical slopes and its applications in slope engineering design. The depth of tension crack and critical slope height are derived from differential equations, which are different from those given by Rankine "state of stress" earth pressure theory. Regardless the difference between the new method presented in this paper and the Rankine theory, their calculation results are almost identical. The results also confirmed that the sliding body slides along the limit angle of the slide. The relationship between critical crack depth and distance from the slope edge, integrating with location of the sliding plane maximum, once can determine the basic (free segment) length of a ground anchor or an earth bar. In addition, the C value could be determined if the both crack depth and distance from the slope edge were measured. The authors also confirmed that active earth pressure equals to the driving force for slide. The new formula reflects physical characterization and reality more closely. In realizing that critical slope height is reduced after a crack is generated within the slope, the authors presented several guidelines for design and construction of vertical slopes.
This paper presents new formulas related to limit equilibrium analysis of the vertical slopes and its applications in slope engineering design. The depth of tension crack and critical slope height are derived from differential equations, which are different from those given by Rankine "state of stress" earth pressure theory. Regardless the difference between the new method presented in this paper and the Rankine theory, their calculation results are almost identical. The results also confirmed that the sliding body slides along the limit angle of the slide. The relationship between critical crack depth and distance from the slope edge, integrating with location of the sliding plane maximum, once can determine the basic (free segment) length of a ground anchor or an earth bar. In addition, the C value could be determined if the both crack depth and distance from the slope edge were measured. The authors also confirmed that active earth pressure equals to the driving force for slide. The new formula reflects physical characterization and reality more closely. In realizing that critical slope height is reduced after a crack is generated within the slope, the authors presented several guidelines for design and construction of vertical slopes.
2008, 16(S1): 257-261.
Soft soil has many special properties which are different from other kinds of soil, such as: high natural moisture content, great void ratio, large compressibility, low shear strength and bearing capacity. Accordingly, the settlement of highway soft soil subgrade has special laws. This paper analysed the settlement laws of soft soil subgrade using FEM software ABAQUS, and made some relative calculation combined project examples, simulated the settlement of soft soil subgrade with different velocity of load embankment, different width of embankment, and different Young's modulus of fill soil to confirm settlement laws of soft soil subgrade. At last this paper makd some conclusions and gave some advices to soft soil subgrade reinforce, construction and detection.
Soft soil has many special properties which are different from other kinds of soil, such as: high natural moisture content, great void ratio, large compressibility, low shear strength and bearing capacity. Accordingly, the settlement of highway soft soil subgrade has special laws. This paper analysed the settlement laws of soft soil subgrade using FEM software ABAQUS, and made some relative calculation combined project examples, simulated the settlement of soft soil subgrade with different velocity of load embankment, different width of embankment, and different Young's modulus of fill soil to confirm settlement laws of soft soil subgrade. At last this paper makd some conclusions and gave some advices to soft soil subgrade reinforce, construction and detection.
2008, 16(S1): 262-266.
A new kind of organic soil stabilizer patent products—STW ecotypic soil stabilizer series which is self-developed by authors' group, is presented in this paper. The basic principle, basic formula, basic property and stability performance of STW soil stabilizer are investigated, and the water-stability,anti-erosion ability and vegetation growth of clay stabilized by STW type stabilizers is tested. The experimental results indicate that the STW soil stabilizer can improve the water-stability and anti-erosion, has a good effect on the slope protection, soil anti-erosion, slope stability and vegetation growth. These results also show its mighty future of application.
A new kind of organic soil stabilizer patent products—STW ecotypic soil stabilizer series which is self-developed by authors' group, is presented in this paper. The basic principle, basic formula, basic property and stability performance of STW soil stabilizer are investigated, and the water-stability,anti-erosion ability and vegetation growth of clay stabilized by STW type stabilizers is tested. The experimental results indicate that the STW soil stabilizer can improve the water-stability and anti-erosion, has a good effect on the slope protection, soil anti-erosion, slope stability and vegetation growth. These results also show its mighty future of application.
2008, 16(S1): 267-269.
In the recent years, hydropower construction is speeding up, the time of the survey and testing is very pressing, and the working cycle of the survey and design shorten at preparation stage, it causes that survey work is insufficient and the engineering geological condition of part buildings can not be found out in detail. Meanwhile, because of catch the time limit in the process of construction, the parts that need take engineering treatment measures don't be timely treated, result in the engineering geological condition worsening and emergency project. Accordingly construction period is delayed and project investment is increased. Combining with engineering example, the paper offers basic recognition and thinking.
In the recent years, hydropower construction is speeding up, the time of the survey and testing is very pressing, and the working cycle of the survey and design shorten at preparation stage, it causes that survey work is insufficient and the engineering geological condition of part buildings can not be found out in detail. Meanwhile, because of catch the time limit in the process of construction, the parts that need take engineering treatment measures don't be timely treated, result in the engineering geological condition worsening and emergency project. Accordingly construction period is delayed and project investment is increased. Combining with engineering example, the paper offers basic recognition and thinking.
2008, 16(S1): 270-273.
According to the increasing of China economy, more and more domestic construct and consultant company will involve in foreign market, and face different opportunity and challenge. Based on field work of soil investigation and geotechnical analysis of The proposed second Penang Second Bridge, This paper show the differences between Chinese code or Standard Methods and the British Standard code so that give some advices to chin the in order to reduce risk when China company have engineering in in British Commonwealth of Nations, Southeast Asia
According to the increasing of China economy, more and more domestic construct and consultant company will involve in foreign market, and face different opportunity and challenge. Based on field work of soil investigation and geotechnical analysis of The proposed second Penang Second Bridge, This paper show the differences between Chinese code or Standard Methods and the British Standard code so that give some advices to chin the in order to reduce risk when China company have engineering in in British Commonwealth of Nations, Southeast Asia
2008, 16(S1): 274-277.
With the expansion of engineering investigation fields and scale in China, data of investigation become more and more large and complex. How to use computer technology in particular GIS technology to effectively organize and manage survey data has become a hot and difficult point in investigation techniques. The traditional two-dimensional GIS technology is difficult to describe underground complex geological environment. Three-dimensional GIS technology can be used to solve this problem.In the paper based on the analysis of three-dimensional GIS technology features and the industry's needs on engineering investigations the application of three-dimensional GIS on engineering investigation was discussed. As well as the three-dimensional supporting information system built by authors was introduced. And the system was tested fully with an example. A comprehensive inspection was conducted.
With the expansion of engineering investigation fields and scale in China, data of investigation become more and more large and complex. How to use computer technology in particular GIS technology to effectively organize and manage survey data has become a hot and difficult point in investigation techniques. The traditional two-dimensional GIS technology is difficult to describe underground complex geological environment. Three-dimensional GIS technology can be used to solve this problem.In the paper based on the analysis of three-dimensional GIS technology features and the industry's needs on engineering investigations the application of three-dimensional GIS on engineering investigation was discussed. As well as the three-dimensional supporting information system built by authors was introduced. And the system was tested fully with an example. A comprehensive inspection was conducted.
2008, 16(S1): 278-281.
Based on the researches on the technology of geological radar detection, the structure and geophysical characteristics of the concrete wall-protection, this paper discusses the feasibility, work method and technology of no-damage detection of the thickness of the concrete wall-protection with the technology of geological radar detection, which was confirmed by the examples with their reliable and accurate results.
Based on the researches on the technology of geological radar detection, the structure and geophysical characteristics of the concrete wall-protection, this paper discusses the feasibility, work method and technology of no-damage detection of the thickness of the concrete wall-protection with the technology of geological radar detection, which was confirmed by the examples with their reliable and accurate results.
2008, 16(S1): 282-287.
In order to get working mechanism of pedestal piles in soft soils, a group of field vertical loading tests were performed on pedestal and normal piles at a site in soft soils to make comparative study.This paper analyzes the testing information, and explore the bearing characteristic and capacity of pedestal piles, discuss the working process of pile vertical bearing capacity,also relations between lateral friction force、the force at the end of the pile and pile vertical bearing capacity. The study indicates that pedestal pile could work very well in soft soils,and the pedestal pile could bring potential bearing capacity of the supporting layer into full play and remarkably enhance the pile's bearing capacity and reduce the settlement.The study indicates that working mechanism of pedestal piles in soft soils is somewhat different with that in other soils.
In order to get working mechanism of pedestal piles in soft soils, a group of field vertical loading tests were performed on pedestal and normal piles at a site in soft soils to make comparative study.This paper analyzes the testing information, and explore the bearing characteristic and capacity of pedestal piles, discuss the working process of pile vertical bearing capacity,also relations between lateral friction force、the force at the end of the pile and pile vertical bearing capacity. The study indicates that pedestal pile could work very well in soft soils,and the pedestal pile could bring potential bearing capacity of the supporting layer into full play and remarkably enhance the pile's bearing capacity and reduce the settlement.The study indicates that working mechanism of pedestal piles in soft soils is somewhat different with that in other soils.
2008, 16(S1): 288-291.
FEM was performed to analyze one ground improvement project using plastic wick drain and preloading. The numerical results were compared to those obtained by insitu measurement and both were in good agreement.
FEM was performed to analyze one ground improvement project using plastic wick drain and preloading. The numerical results were compared to those obtained by insitu measurement and both were in good agreement.
2008, 16(S1): 292-295.
Drilling is a common geologic prospecting method, which is meticulous, intuitive and accurate. However it also has its limitations just like high cost, complicated operation and limited drill holes. So the drilling method can't inform completely the area geologic condition. For fast, easy to complete large multi-point test, authors apply sound reflection technology to geologic prospecting work of WANGJIA housing estate new relocation site in Sichuan ABA. In this paper, HSP sound wave reflection theory is introduced in detail, and geological foundation geological conditions can be speculated using time-domain and frequency domain analysis of geological changes, based on further investigation of geological structure. The results of contrast test verify that HSP sound wave reflection method used to launch geological survey is simple and feasible, fast and effective. This paper provides an example for similar projects in analysis and speculation of sound wave reflection method.
Drilling is a common geologic prospecting method, which is meticulous, intuitive and accurate. However it also has its limitations just like high cost, complicated operation and limited drill holes. So the drilling method can't inform completely the area geologic condition. For fast, easy to complete large multi-point test, authors apply sound reflection technology to geologic prospecting work of WANGJIA housing estate new relocation site in Sichuan ABA. In this paper, HSP sound wave reflection theory is introduced in detail, and geological foundation geological conditions can be speculated using time-domain and frequency domain analysis of geological changes, based on further investigation of geological structure. The results of contrast test verify that HSP sound wave reflection method used to launch geological survey is simple and feasible, fast and effective. This paper provides an example for similar projects in analysis and speculation of sound wave reflection method.
2008, 16(S1): 296-301.
The holes on the electromagnetic wave Perspective methods, large-scale works in the foundation rock wells along the axis model that is the establishment of Perspective (mathematics, physics - the geological model), in a certain distance away from the launch and receive two holes, deep holes in the different rock Soil launch electromagnetic waves, electromagnetic wave frequency bands for Jizhao Hertz to tens of MHz, the receiver in another hole data collection. Numerical data received will be dealt with imaging, system-generated different colours physics, the geological structure of plans that CT image. Guizhou taojiagou bridge pier foundation works landslide as an example, with a small amount of drilling carried out electromagnetic wave perspective, given the landslide, the sliding surface of the image than the quantitative and numerical results of geological disasters in the project evaluation and forecasting.
The holes on the electromagnetic wave Perspective methods, large-scale works in the foundation rock wells along the axis model that is the establishment of Perspective (mathematics, physics - the geological model), in a certain distance away from the launch and receive two holes, deep holes in the different rock Soil launch electromagnetic waves, electromagnetic wave frequency bands for Jizhao Hertz to tens of MHz, the receiver in another hole data collection. Numerical data received will be dealt with imaging, system-generated different colours physics, the geological structure of plans that CT image. Guizhou taojiagou bridge pier foundation works landslide as an example, with a small amount of drilling carried out electromagnetic wave perspective, given the landslide, the sliding surface of the image than the quantitative and numerical results of geological disasters in the project evaluation and forecasting.
2008, 16(S1): 302-306.
GPR is a kind of physical detecting technology, which has high efficiency, high resolution and non-destruction; it is a useful geophysical detection technique in detecting underground cavity. The cavity underground tunnel can cause disaster such as the road surface l sinking, lining crazing and top floor collapsing, etc., affecting the safety of tunnel. It's important to accurately detect cavity underground tunnel and take corresponding measures to insure the tunnel's safety. According to the process of the coal pits detecting in the tunnels of Mountain Lion, this issue introduces the application of Ground Penetrating Radar to coal kiln in tunnel.
GPR is a kind of physical detecting technology, which has high efficiency, high resolution and non-destruction; it is a useful geophysical detection technique in detecting underground cavity. The cavity underground tunnel can cause disaster such as the road surface l sinking, lining crazing and top floor collapsing, etc., affecting the safety of tunnel. It's important to accurately detect cavity underground tunnel and take corresponding measures to insure the tunnel's safety. According to the process of the coal pits detecting in the tunnels of Mountain Lion, this issue introduces the application of Ground Penetrating Radar to coal kiln in tunnel.
STUDY ON BACKFILL SCHEMES COMPARISON OF A SURFACE CAVITY CAUSED BY TUNNEL COLLAPSE IN LOESS DISTRICT
2008, 16(S1): 307-312.
A tunnel in loess district collapsed due to heavy rain, resulting in a cylindrical cavity on surface. Two schemes, reinforce-and-cover and cut-and-cover, have been brought forward for backfill, and compared in tunnel structure moment and construction cost to decide which one should be adopted. Tunnel structure moment can be calculated by ANSYS, using load-structure method and strata-structure method, respectively. It comes to conclusion that tunnel structure would be safer and construction more economical if employed the first scheme to refill the cavity.
A tunnel in loess district collapsed due to heavy rain, resulting in a cylindrical cavity on surface. Two schemes, reinforce-and-cover and cut-and-cover, have been brought forward for backfill, and compared in tunnel structure moment and construction cost to decide which one should be adopted. Tunnel structure moment can be calculated by ANSYS, using load-structure method and strata-structure method, respectively. It comes to conclusion that tunnel structure would be safer and construction more economical if employed the first scheme to refill the cavity.
2008, 16(S1): 313-316.
This paper discusses apply ground-penetrating radar to detect adverse geology, which subway tunnel construction may encounter, such as underground cavity, underground river, building piles. To recognize and simulate those typical adverse geological GPR images, in order to improve ground-penetrating radar data interpretation library.
This paper discusses apply ground-penetrating radar to detect adverse geology, which subway tunnel construction may encounter, such as underground cavity, underground river, building piles. To recognize and simulate those typical adverse geological GPR images, in order to improve ground-penetrating radar data interpretation library.
2008, 16(S1): 317-319.
Rock tensile strength is very important. It is one of the important aspects of geotechnical engineering, geological engineering in the design, construction and acceptability. However, most methods for testing rock tensile strength are not reliable. We should pay sufficient attention to this reliability issue. The article specifically emphasizes why bending tensile test is not reliable.
Rock tensile strength is very important. It is one of the important aspects of geotechnical engineering, geological engineering in the design, construction and acceptability. However, most methods for testing rock tensile strength are not reliable. We should pay sufficient attention to this reliability issue. The article specifically emphasizes why bending tensile test is not reliable.
2008, 16(S1): 320-325.
The Flat Dilatometer Test (DMT) have a lot of virtues. DMT has already been used somewhere in our country. However, the regionally otherness of geotechnical engineering itself, other regions' results and experiential formula can not be fully applied. After compared with the researching status, we amend the theoretical formula of in-situ initial horizontal stress, then gets the expression of Hangzhou. Compared with the data and values from the soil tests of subway projects in Hangzhou, and provide it can be used well in Hangzhou.
The Flat Dilatometer Test (DMT) have a lot of virtues. DMT has already been used somewhere in our country. However, the regionally otherness of geotechnical engineering itself, other regions' results and experiential formula can not be fully applied. After compared with the researching status, we amend the theoretical formula of in-situ initial horizontal stress, then gets the expression of Hangzhou. Compared with the data and values from the soil tests of subway projects in Hangzhou, and provide it can be used well in Hangzhou.
2008, 16(S1): 326-328.
In this paper, proposed a flat load test at the end of drilling deep holes, introduced the deep pressure systems, communication systems and the composition of observing systems of a flat load test and analyzed this process. Practice has proved that the flat load test at the end of a deep hole is a feasible and effective project in deep flat load test.
In this paper, proposed a flat load test at the end of drilling deep holes, introduced the deep pressure systems, communication systems and the composition of observing systems of a flat load test and analyzed this process. Practice has proved that the flat load test at the end of a deep hole is a feasible and effective project in deep flat load test.
2008, 16(S1): 329-333.
This article for basis with a construction engineering abundant of prognosticate data reinforced concrete drill-hole pile static loading test in Xi'an City, neither to analyse and evaluate the bored pile quality and the pile integrity; nor certaine those parameter such as the ultimate bearing capacity,the around pile shaft ultimate resistance and the the end bearing capacity of pile etc. This pile testing result has been certained the around pile shaft ultimate resistance each layer soil and the ultimate bearing capacity layer that 《Technical code for building pile foundation 》 (JGJ94-94) investigate the suggestions about 10%~60% and 50% with the yeotechnical engineering reconnaissance report investigate the suggestions。But this reinforced concrete drill-hole pile testing under the conditions carry mainly from the around pile shaft ultimate resistance, the end bearing capacity of pile don't develop all, only developped about 20% ~60%. Throuth this testing result of analytical research, This building the long of the reinforced concrete drill-hole pile not only can reduce 5 meters from Original design, but also economize a great deal of funds, save work a period again, obtain well performance.
This article for basis with a construction engineering abundant of prognosticate data reinforced concrete drill-hole pile static loading test in Xi'an City, neither to analyse and evaluate the bored pile quality and the pile integrity; nor certaine those parameter such as the ultimate bearing capacity,the around pile shaft ultimate resistance and the the end bearing capacity of pile etc. This pile testing result has been certained the around pile shaft ultimate resistance each layer soil and the ultimate bearing capacity layer that 《Technical code for building pile foundation 》 (JGJ94-94) investigate the suggestions about 10%~60% and 50% with the yeotechnical engineering reconnaissance report investigate the suggestions。But this reinforced concrete drill-hole pile testing under the conditions carry mainly from the around pile shaft ultimate resistance, the end bearing capacity of pile don't develop all, only developped about 20% ~60%. Throuth this testing result of analytical research, This building the long of the reinforced concrete drill-hole pile not only can reduce 5 meters from Original design, but also economize a great deal of funds, save work a period again, obtain well performance.
2008, 16(S1): 334-339.
As a new kind of in-situ test technique originated in 1980s, the piezocone penetration test (CPTU) has especially been fit for engineering investigation of soft clay and commonly used in the western developed countries because of its advantages. In the first place, the paper introduces the development of CPTU in brief, expounding the equipment and operation procedures. With summarizing literature works, the engineering properties of soft clay are evaluated from CPTU data, particularly in the evaluation of stress history, strength, deformation, consolidation and permeability characteristics. Finally, some conclusions on the CPTU are finally presented.
As a new kind of in-situ test technique originated in 1980s, the piezocone penetration test (CPTU) has especially been fit for engineering investigation of soft clay and commonly used in the western developed countries because of its advantages. In the first place, the paper introduces the development of CPTU in brief, expounding the equipment and operation procedures. With summarizing literature works, the engineering properties of soft clay are evaluated from CPTU data, particularly in the evaluation of stress history, strength, deformation, consolidation and permeability characteristics. Finally, some conclusions on the CPTU are finally presented.
2008, 16(S1): 340-344.
The cast-in-place pile with all expanded drive (CIPPWAED) is a new kind of cast in-situ pile, because it is formed by all expanded drive during its construction process, the bottom and the lower extended cylinder part of the pile body shape likes sugar coated haws on a stick, or maize stick. The point resistance and the skin resistance of single pile is increasing obviously after the all expanded drive construction, based on national code, the calculation results of the skin resistance is not precise, further more, it can not disclose the mechanisms of the pile. In this paper, by collecting the main factors which affect the properties of bearing capacity, to analyze the extrusion soil effect and the secondary extrusion soil effect, based on the adaptive neuro-fuzzy inference system, with the measured materials of the static loading test in-situ (the time from 1995 to nowadays), to apply the fuzzy logic toolbox to build the ANFIS model, and to optimize the ANN with immune genetic method, and then study the ultimate bearing capacity of the pile with all expanded drive. The prediction results shows that it brings a new bright future for this predicting method because of the calculation mode of this kind pile overcome the shortcomings of the bearing capacity calculated by empirical formulation and FEM method.
The cast-in-place pile with all expanded drive (CIPPWAED) is a new kind of cast in-situ pile, because it is formed by all expanded drive during its construction process, the bottom and the lower extended cylinder part of the pile body shape likes sugar coated haws on a stick, or maize stick. The point resistance and the skin resistance of single pile is increasing obviously after the all expanded drive construction, based on national code, the calculation results of the skin resistance is not precise, further more, it can not disclose the mechanisms of the pile. In this paper, by collecting the main factors which affect the properties of bearing capacity, to analyze the extrusion soil effect and the secondary extrusion soil effect, based on the adaptive neuro-fuzzy inference system, with the measured materials of the static loading test in-situ (the time from 1995 to nowadays), to apply the fuzzy logic toolbox to build the ANFIS model, and to optimize the ANN with immune genetic method, and then study the ultimate bearing capacity of the pile with all expanded drive. The prediction results shows that it brings a new bright future for this predicting method because of the calculation mode of this kind pile overcome the shortcomings of the bearing capacity calculated by empirical formulation and FEM method.
2008, 16(S1): 345-349.
Flat loading test is an available method to determine the characteristic value of subsoil bearing capacity, and was nominated by standardization code. As its shortage of taking time and money, it was much more important for the testing data to be used sufficiently. By analyzing an engineering information, this thesis adopted ways and means, such as choosing different settlement value standard of pressure as bearing capacity, comparing the site test result to the lab etc. to solve the discrepancy of the flat loading test result and gain the index of bearing capacity. These methods seem disagreement to the standardization code, but accurately it was much more corresponding to the principle of the code. So it would have some reference effectiveness for other engineering.
Flat loading test is an available method to determine the characteristic value of subsoil bearing capacity, and was nominated by standardization code. As its shortage of taking time and money, it was much more important for the testing data to be used sufficiently. By analyzing an engineering information, this thesis adopted ways and means, such as choosing different settlement value standard of pressure as bearing capacity, comparing the site test result to the lab etc. to solve the discrepancy of the flat loading test result and gain the index of bearing capacity. These methods seem disagreement to the standardization code, but accurately it was much more corresponding to the principle of the code. So it would have some reference effectiveness for other engineering.
2008, 16(S1): 350-353.
Dynamic compaction replacement technique shows great advantages on processing, saving of construction materials and construction time, as well as cost. With a real testing project, the design, construction as well as testing techniques are discussed in this paper. Results show that, soils around and below dynamic compaction piles can be significantly compacted, and the bearing capacity of subsoil can be greatly improved.
Dynamic compaction replacement technique shows great advantages on processing, saving of construction materials and construction time, as well as cost. With a real testing project, the design, construction as well as testing techniques are discussed in this paper. Results show that, soils around and below dynamic compaction piles can be significantly compacted, and the bearing capacity of subsoil can be greatly improved.
2008, 16(S1): 354-356.
Based on surveying and analyzing the section of soil-rock high slope, used pre-stressed cable to prevent land-slide. This method solved the technical problems of forming the hole in the soil-rock and lattice beam construction. In this paper also introduction the pre-stressed cable field testing methods and tested results. The results meet the design requirements and the relevant norms.
Based on surveying and analyzing the section of soil-rock high slope, used pre-stressed cable to prevent land-slide. This method solved the technical problems of forming the hole in the soil-rock and lattice beam construction. In this paper also introduction the pre-stressed cable field testing methods and tested results. The results meet the design requirements and the relevant norms.
2008, 16(S1): 357-360.
A serious pile accident occurred after the construction of the jaked pile in a high-rise building, which is build in soft soil site. The reason is analyzed based on the thorough analysis investigation, several methods are adopted in the reinforcement. The security danger has been eliminated, and the building service life is guaranteed.
A serious pile accident occurred after the construction of the jaked pile in a high-rise building, which is build in soft soil site. The reason is analyzed based on the thorough analysis investigation, several methods are adopted in the reinforcement. The security danger has been eliminated, and the building service life is guaranteed.
2008, 16(S1): 361-364.
With the fast development of the highway construction in China,there are usually approach slab fracture, bridgehead vehicle jump at the joint of road and bridge because of structure and feature, construction, rainfall and so on. It affects severely the operation of the high way. This study classify the effect of the backfills on abutment in to three types: the earth pressure behind abutment, differential settlement and the load result from soft roadbed sliding. This study has analyzed the cause of them, quantization indexes and research survey of them.
With the fast development of the highway construction in China,there are usually approach slab fracture, bridgehead vehicle jump at the joint of road and bridge because of structure and feature, construction, rainfall and so on. It affects severely the operation of the high way. This study classify the effect of the backfills on abutment in to three types: the earth pressure behind abutment, differential settlement and the load result from soft roadbed sliding. This study has analyzed the cause of them, quantization indexes and research survey of them.
2008, 16(S1): 365-368.
The paper firstly points out the causes and the characters of the negative friction of pile foundation, and also introduces its unfavorable effects on pile foundation. According to some correlated standards and regulations, then it gives some calculation methods of negative friction of pile foundation, including: the location of the neutral-point, the determination of the negative friction and the bearing-capacity check of the pile founding. Lastly, it introduces some methods to reducing the effect of the negative friction of pile foundation.
The paper firstly points out the causes and the characters of the negative friction of pile foundation, and also introduces its unfavorable effects on pile foundation. According to some correlated standards and regulations, then it gives some calculation methods of negative friction of pile foundation, including: the location of the neutral-point, the determination of the negative friction and the bearing-capacity check of the pile founding. Lastly, it introduces some methods to reducing the effect of the negative friction of pile foundation.
2008, 16(S1): 369-372.
The paper presents the definition and formation mechanism of single pile negative skin friction, details the state of art about single pile negative skin friction, and put forward the problems still unsolved.
The paper presents the definition and formation mechanism of single pile negative skin friction, details the state of art about single pile negative skin friction, and put forward the problems still unsolved.
2008, 16(S1): 373-376.
JG (Jet Grouting) soil-cement-Pile strengthened pile (for short JPP)technology is an advanced technology and economic environment of new technology patents. Which was developped after years of study and practice, aim at coastal land area of soft pile lateral friction and lower-end resistance characteristics. JG(Jet Grouting) soil-cement-Pile strengthened pile combinations of high jet by the High Pressure Jet piles and piles into one of the core concentric pile composed by the pile of reinforced concrete core, of concrete, steel and other materials. JG use of reinforced soil, through hard soil or bottom of the pile-soil reinforcement and improve pile lateral friction and end resistance, the core pile (precast piles, sink steel tube Piles and piles of steel, etc.) have sufficient cross-section of the pile Strength, to satisfy the load demand, High-pressure JG pile and high-core pile are effective combination, pile bearing capacity significantly increased. So the pile has low-cost, economic environment, high bearing capacity of the notable features etc. Tangshan Lanxin Glass project use this pile, Which Successfully resolved the problems of the ordinary pile of prefabricated difficult to penetrate the silty material and silty sand layer, avoid soil extrusion effect, raise the pile bearing capacity, reduce the project cost, economic efficiency and social Obvious benefits.
JG (Jet Grouting) soil-cement-Pile strengthened pile (for short JPP)technology is an advanced technology and economic environment of new technology patents. Which was developped after years of study and practice, aim at coastal land area of soft pile lateral friction and lower-end resistance characteristics. JG(Jet Grouting) soil-cement-Pile strengthened pile combinations of high jet by the High Pressure Jet piles and piles into one of the core concentric pile composed by the pile of reinforced concrete core, of concrete, steel and other materials. JG use of reinforced soil, through hard soil or bottom of the pile-soil reinforcement and improve pile lateral friction and end resistance, the core pile (precast piles, sink steel tube Piles and piles of steel, etc.) have sufficient cross-section of the pile Strength, to satisfy the load demand, High-pressure JG pile and high-core pile are effective combination, pile bearing capacity significantly increased. So the pile has low-cost, economic environment, high bearing capacity of the notable features etc. Tangshan Lanxin Glass project use this pile, Which Successfully resolved the problems of the ordinary pile of prefabricated difficult to penetrate the silty material and silty sand layer, avoid soil extrusion effect, raise the pile bearing capacity, reduce the project cost, economic efficiency and social Obvious benefits.
2008, 16(S1): 377-381.
The in-situ stress parameters have become one of the most essential data for the stability design of a underground project, but there exist some misunderstandings on how to use in-situ stress measurements. Through analyzing the linear fitting plot of measured in-situ stress data versus depth, many problems can be found, such as scattered data, unstable correlation coefficient. Here, internationally-accepted Sheorey theory is introduced, which has taken the gravitational action, Poisson's effect, lithology and other factors into consideration, and this theory has defined one general variation law of the horizontal stress in the upper crust versus depth as well. One planned water-sealed oil reservoir is located in the Bohai Gulf, Liaoning Province. During the feasibility research stage of the project, hydrofracturing in-situ stress measurements have been done in two boreholes, but the measured data is scattered and hard to select one rational value for the design. By comparing the fitting effect based on the Sheorey theory with that of linear fitting, this theory can define the variation law of measured in-situ stress versus depth very well, and offer proper in-situ stress values for the project design. This method is of great significance to the design of other project.
The in-situ stress parameters have become one of the most essential data for the stability design of a underground project, but there exist some misunderstandings on how to use in-situ stress measurements. Through analyzing the linear fitting plot of measured in-situ stress data versus depth, many problems can be found, such as scattered data, unstable correlation coefficient. Here, internationally-accepted Sheorey theory is introduced, which has taken the gravitational action, Poisson's effect, lithology and other factors into consideration, and this theory has defined one general variation law of the horizontal stress in the upper crust versus depth as well. One planned water-sealed oil reservoir is located in the Bohai Gulf, Liaoning Province. During the feasibility research stage of the project, hydrofracturing in-situ stress measurements have been done in two boreholes, but the measured data is scattered and hard to select one rational value for the design. By comparing the fitting effect based on the Sheorey theory with that of linear fitting, this theory can define the variation law of measured in-situ stress versus depth very well, and offer proper in-situ stress values for the project design. This method is of great significance to the design of other project.
2008, 16(S1): 382-385.
It introduced the present development condition and prospect of Water Source Heat Pumps (WSHP), and the main research direction at home and abroad. Aim at the lack of studying on WSHP, a set of combine instrument to imitate WSHP was established and relevant simulation experiment was carried out. The experiment principle, test-bed composition, experimental sample preparation process, experimental steps and the various experimental equipment design parameters were introduced. The experimental results were analyzed and simulated. Through controlling different temperature and different recharging water volume, we found the following heat transfer characteristics: Increasing water recharging volume is less than the impact of increasing water recharging temperature on the surrounding sand temperature. The thermal diffusion of recharging water down is stronger than upward. Through controlling recharging water volume and temperature, the affected areas of sand temperature in the horizontal and vertical direction was drawn on, Which provided reference data for the development of water-source heat pump technology. Two -dimensional temperature field was simulated and contrasted with water recharge experiment data. According to results of the experiment, the conductivity of saturated was verified sand by the Fourier's Law, and the practical significance of Indoor-water source heat pump simulator and theory analysis on the water-source heat pump's design was discussed.
It introduced the present development condition and prospect of Water Source Heat Pumps (WSHP), and the main research direction at home and abroad. Aim at the lack of studying on WSHP, a set of combine instrument to imitate WSHP was established and relevant simulation experiment was carried out. The experiment principle, test-bed composition, experimental sample preparation process, experimental steps and the various experimental equipment design parameters were introduced. The experimental results were analyzed and simulated. Through controlling different temperature and different recharging water volume, we found the following heat transfer characteristics: Increasing water recharging volume is less than the impact of increasing water recharging temperature on the surrounding sand temperature. The thermal diffusion of recharging water down is stronger than upward. Through controlling recharging water volume and temperature, the affected areas of sand temperature in the horizontal and vertical direction was drawn on, Which provided reference data for the development of water-source heat pump technology. Two -dimensional temperature field was simulated and contrasted with water recharge experiment data. According to results of the experiment, the conductivity of saturated was verified sand by the Fourier's Law, and the practical significance of Indoor-water source heat pump simulator and theory analysis on the water-source heat pump's design was discussed.
2008, 16(S1): 386-390.
Starting from the governing equations of asymmetric consolidation of soil with compressible constituents, together with the intermediate variables, the technique of Fourier expansions with respect to coordinate θ, Laplace-Hankel transform with respect to time t and coordinate r, two sets of uncoupled transfer matrixes of 6 order and 2 order for a single layer soil with compressible constituents are acquired after using the displacement functions suggested by Schiffman and Fungaroli. Based on the continuity and the boundary conditions, the transfer matrix method is utilized to derive the uncoupled solution for the multi-layered soil with compressible constituents in the transform domain. By the inversion of the Laplace-Hankel transform, the solution for the consolidation of a multi-layered soil with compressible constituents in the physical domain is obtained. Numerical analysis is carried out by the computer program, and the effect on the process of consolidation for the compressibility of pore fluid is also discussed.
Starting from the governing equations of asymmetric consolidation of soil with compressible constituents, together with the intermediate variables, the technique of Fourier expansions with respect to coordinate θ, Laplace-Hankel transform with respect to time t and coordinate r, two sets of uncoupled transfer matrixes of 6 order and 2 order for a single layer soil with compressible constituents are acquired after using the displacement functions suggested by Schiffman and Fungaroli. Based on the continuity and the boundary conditions, the transfer matrix method is utilized to derive the uncoupled solution for the multi-layered soil with compressible constituents in the transform domain. By the inversion of the Laplace-Hankel transform, the solution for the consolidation of a multi-layered soil with compressible constituents in the physical domain is obtained. Numerical analysis is carried out by the computer program, and the effect on the process of consolidation for the compressibility of pore fluid is also discussed.
2008, 16(S1): 391-394.
Through single pile vertical resistant to vertical static load experiment and single pile horizontal static load experiment on PHC pre-pressed pipe pile and bored pile with the same diameter and length, this paper analyzed pile head deformation and bearing performance of the two kinds of piles under the circumstances of vertical load and horizontal load. The results indicate that, the vertical load bearing performance differs little between the two piles. PHC pre-pressed pipe pile has a little more vertical bearing capacity than bored pile, while it has nearly the same horizontal bearing capacity with bored pile, with a little less horizontal deformation. Hence the level resistance coefficient ratio of foundation m calculated from PHC pre-pressed pipe pile is a little higher than bored pile.
Through single pile vertical resistant to vertical static load experiment and single pile horizontal static load experiment on PHC pre-pressed pipe pile and bored pile with the same diameter and length, this paper analyzed pile head deformation and bearing performance of the two kinds of piles under the circumstances of vertical load and horizontal load. The results indicate that, the vertical load bearing performance differs little between the two piles. PHC pre-pressed pipe pile has a little more vertical bearing capacity than bored pile, while it has nearly the same horizontal bearing capacity with bored pile, with a little less horizontal deformation. Hence the level resistance coefficient ratio of foundation m calculated from PHC pre-pressed pipe pile is a little higher than bored pile.
2008, 16(S1): 395-398.
Slope stability assessment is one of important contents of geological disaster assessment for a shutting down abandoned mine. Based in Beijing Fengtai District Qianling mountain area surrounding the exposed mountain ecological restoration project slope stability analysis, this paper expatiates the application of stereographic projection method. It could be a helpful reference for a similar geological disaster assessment.
Slope stability assessment is one of important contents of geological disaster assessment for a shutting down abandoned mine. Based in Beijing Fengtai District Qianling mountain area surrounding the exposed mountain ecological restoration project slope stability analysis, this paper expatiates the application of stereographic projection method. It could be a helpful reference for a similar geological disaster assessment.
2008, 16(S1): 399-402.
The groundwater has many effects on stability in gravel soil slopes. There are some different views on how to consider the effects of the pore water pressure and the penetration on stability assessment. This paper focuses on the different effects of the pore water pressure and the penetration in the stability calculation. Based on the results of the analysis on the Xiwulu slope in Badong county, it's more effective and available to consider the penetration and the effective bulk density below the saturation line in the heavy rain conditions. In some standards, the pore water pressure and the penetration are both considered on the stability calculation is inappropriate.
The groundwater has many effects on stability in gravel soil slopes. There are some different views on how to consider the effects of the pore water pressure and the penetration on stability assessment. This paper focuses on the different effects of the pore water pressure and the penetration in the stability calculation. Based on the results of the analysis on the Xiwulu slope in Badong county, it's more effective and available to consider the penetration and the effective bulk density below the saturation line in the heavy rain conditions. In some standards, the pore water pressure and the penetration are both considered on the stability calculation is inappropriate.
2008, 16(S1): 403-406.
This paper presents the solutions for three dimensional Biot's consolidation problem of multilayered soils, and the compressibility of pore fluid is considered. Based on the equations of three dimensional Biot's consolidation with compressible constituents, by introducing displacement functions, intermediate variables and the Laplace-Fourier transform, two sets of transfer matrix of 6 order and 2 order are obtained. The solutions for three dimensional Biot's consolidation problem of multilayered soils with compressible constituents in the transform domain are obtained by using the transfer matrix method and combined with the continuity conditions and the boundary conditions. The actual solutions can be acquired by inverting the Laplace-Fourier transform. Corresponding program is carried out to analyze the influence of the compressibility of pore fluid on the consolidation behavior of the soils.
This paper presents the solutions for three dimensional Biot's consolidation problem of multilayered soils, and the compressibility of pore fluid is considered. Based on the equations of three dimensional Biot's consolidation with compressible constituents, by introducing displacement functions, intermediate variables and the Laplace-Fourier transform, two sets of transfer matrix of 6 order and 2 order are obtained. The solutions for three dimensional Biot's consolidation problem of multilayered soils with compressible constituents in the transform domain are obtained by using the transfer matrix method and combined with the continuity conditions and the boundary conditions. The actual solutions can be acquired by inverting the Laplace-Fourier transform. Corresponding program is carried out to analyze the influence of the compressibility of pore fluid on the consolidation behavior of the soils.
2008, 16(S1): 407-410.
This paper verified reliability of the large-diameter bored pile simulation with finite difference models. On the basis, the paper simulated the model of the bored pile with lower part tilted by FLAC3D, and analyzed the changes of bearing capacity and stability. The conclusion is that the change of capacity and stability is insignificant to practical engineering if the slope is in a certain range can be reached by analyzing the behavior of pile.
This paper verified reliability of the large-diameter bored pile simulation with finite difference models. On the basis, the paper simulated the model of the bored pile with lower part tilted by FLAC3D, and analyzed the changes of bearing capacity and stability. The conclusion is that the change of capacity and stability is insignificant to practical engineering if the slope is in a certain range can be reached by analyzing the behavior of pile.
2008, 16(S1): 411-414.
In this paper, we describe the characteristic of general regression neural network. Then the model of predicting the occurrence of liquefaction is proposed after considering the main factors. The supporting data is derived from the results of field tests of the two major earthquakes that took place in Turkey and Taiwan in 1999. After utilizing the multiple regression pretreatment to optimize the input data, the study uses the GRNN to implement the training and validation phase. The results have a higher degree of consistent with the actual situation and clearly demonstrate the capability of the proposed model to assess the liquefaction of soils. Then multiple linear regression is proved to improve the accuracy of forecasts as a good pretreatment method.
In this paper, we describe the characteristic of general regression neural network. Then the model of predicting the occurrence of liquefaction is proposed after considering the main factors. The supporting data is derived from the results of field tests of the two major earthquakes that took place in Turkey and Taiwan in 1999. After utilizing the multiple regression pretreatment to optimize the input data, the study uses the GRNN to implement the training and validation phase. The results have a higher degree of consistent with the actual situation and clearly demonstrate the capability of the proposed model to assess the liquefaction of soils. Then multiple linear regression is proved to improve the accuracy of forecasts as a good pretreatment method.
2008, 16(S1): 415-418.
It is normal to get parameters of rock mass through tests in engineering. Due to consideration of randomicity and illegibility, random-fuzzy method is more reasonable than other usual methods. The core of conventional random-fuzzy method is reflecting the uncertainties by membership function. Though it does not eliminate the influence of mutation points, it decreases that in some extent. In this paper, based on statistics and criterions, the mutation points are chosen and deleted by a more reasonable method, which eliminates the points that have small membership degree. Then, this method is certified through a project.
It is normal to get parameters of rock mass through tests in engineering. Due to consideration of randomicity and illegibility, random-fuzzy method is more reasonable than other usual methods. The core of conventional random-fuzzy method is reflecting the uncertainties by membership function. Though it does not eliminate the influence of mutation points, it decreases that in some extent. In this paper, based on statistics and criterions, the mutation points are chosen and deleted by a more reasonable method, which eliminates the points that have small membership degree. Then, this method is certified through a project.
2008, 16(S1): 419-423.
Cangnan Tiechang Reservoir was a backbone project of the Mazhan Plain low-yielding fields of planning. It mainly designed to flood control, water supply, combined with irrigation and power generation. The dam was designed as masonry arch dam. After the completion of the dam, due to various factors, there were much masonry joints and water-leakage in the vicinity, particularly serious up elevation 89 m. Based on the analysis of geological conditions of the project, core-drilling, underground television and other methods were used to detect diseases of the dam, then a corresponding program of Grouting technology was given. In which drilling and flushing water pressure test were done for filling results detect.
Cangnan Tiechang Reservoir was a backbone project of the Mazhan Plain low-yielding fields of planning. It mainly designed to flood control, water supply, combined with irrigation and power generation. The dam was designed as masonry arch dam. After the completion of the dam, due to various factors, there were much masonry joints and water-leakage in the vicinity, particularly serious up elevation 89 m. Based on the analysis of geological conditions of the project, core-drilling, underground television and other methods were used to detect diseases of the dam, then a corresponding program of Grouting technology was given. In which drilling and flushing water pressure test were done for filling results detect.
2008, 16(S1): 424-427.
The tunneling engineering is complex and concealed. The Digitalization can makes engineer more clear, and displays engineering information more visual and more delight. Because of this engineering management becomes more easy and the Digitalization is used more and more in engineering construction this years. This study relying on the Kuocangshan digintalization system introduced the basic knowledge of the Second Development of AutoCAD with ObjectARX.
The tunneling engineering is complex and concealed. The Digitalization can makes engineer more clear, and displays engineering information more visual and more delight. Because of this engineering management becomes more easy and the Digitalization is used more and more in engineering construction this years. This study relying on the Kuocangshan digintalization system introduced the basic knowledge of the Second Development of AutoCAD with ObjectARX.
2008, 16(S1): 428-431.
In this paper,a improved BP neural network model was used for evaluating the stability of a rock slope has been built by use of the NNtool of MATLAB.Tested the reliability of the neural network model by an analysis of a project in Tianjin .Chose some parameters about rock integrity as the input factors base on the actual situation,collected some rock slope engineering cases to train the model and prove the neural network model is suitable. From tested the results which export from computer,this model is proved to be feasible and it is wider application.
In this paper,a improved BP neural network model was used for evaluating the stability of a rock slope has been built by use of the NNtool of MATLAB.Tested the reliability of the neural network model by an analysis of a project in Tianjin .Chose some parameters about rock integrity as the input factors base on the actual situation,collected some rock slope engineering cases to train the model and prove the neural network model is suitable. From tested the results which export from computer,this model is proved to be feasible and it is wider application.
2008, 16(S1): 432-435.
During the digging construction process of diversion tunnel in Hua Neng BaoXing Power Station, the upper segment encountered the fault zone T65. Due to the emergence of this fault zone,this part has experienced a sudden mud burst and water burst for four times, seriously affecting the progress of the works. This article focuses on the engineering characteristic of this fault zone from the point of engineering geology, and uses full-face curtain grouting combined with ahead small catheter grouting technology to make the fault zone which is rich in water and mud reinforced and water-proofed, and adopts the meathod of step-by-step short footage excavation and timely support in the construction process, ensuring the safety of the tunnel construction in the result. The effective implementation of the measures sets a good example for the construction of similar projects .
During the digging construction process of diversion tunnel in Hua Neng BaoXing Power Station, the upper segment encountered the fault zone T65. Due to the emergence of this fault zone,this part has experienced a sudden mud burst and water burst for four times, seriously affecting the progress of the works. This article focuses on the engineering characteristic of this fault zone from the point of engineering geology, and uses full-face curtain grouting combined with ahead small catheter grouting technology to make the fault zone which is rich in water and mud reinforced and water-proofed, and adopts the meathod of step-by-step short footage excavation and timely support in the construction process, ensuring the safety of the tunnel construction in the result. The effective implementation of the measures sets a good example for the construction of similar projects .
2008, 16(S1): 436-439.
Dynamic triaxial tests were conducted on the renforced soils with 5% lime conetent. Such dynamic properties as cumulative palstic strain, dynamic strain, dynamic stress and resilient module with the cycle times were studied. Based on the test results, the critical dynamic stress of the lime-stabilized soil, the regression coefficients of the correlation between the cumulative plastic strain and cycle time, and the regression coefficients of the correlation between dynamic stress and strain were obtained.
Dynamic triaxial tests were conducted on the renforced soils with 5% lime conetent. Such dynamic properties as cumulative palstic strain, dynamic strain, dynamic stress and resilient module with the cycle times were studied. Based on the test results, the critical dynamic stress of the lime-stabilized soil, the regression coefficients of the correlation between the cumulative plastic strain and cycle time, and the regression coefficients of the correlation between dynamic stress and strain were obtained.
2008, 16(S1): 440-445.
The water pressure test is frequently used in examination boreholes by the Guiyang Branch of the China Aluminum Company for examination of results of the weimuzhujiang the technique in attempting to prevent the alkaline water leakage from a waste water processing field. As the requirements for preventing the leakage of the alkalina water are higher and higher, the current method can not satisfy the examination requirements for checking the leakage degree after guanjiangweimu. More advanced and comprehensive new examination methods are needed for this purpose. This paper presents a comprehensive examination method which combines water pressure test, electro-magnetic CT and cross-hole resistivity techniques to examine the reliability of the weimuzhujiang.
The water pressure test is frequently used in examination boreholes by the Guiyang Branch of the China Aluminum Company for examination of results of the weimuzhujiang the technique in attempting to prevent the alkaline water leakage from a waste water processing field. As the requirements for preventing the leakage of the alkalina water are higher and higher, the current method can not satisfy the examination requirements for checking the leakage degree after guanjiangweimu. More advanced and comprehensive new examination methods are needed for this purpose. This paper presents a comprehensive examination method which combines water pressure test, electro-magnetic CT and cross-hole resistivity techniques to examine the reliability of the weimuzhujiang.
2008, 16(S1): 446-450.
Taking the serious water inrush accident due to coal mining under super-thick hard igneous rock in Huaibei Mining Group for example, hydrologic and engineering geology conditions of the water inrush are investigated and tested. Based on comparison to the characteristics of other water inrush accidence due to coal mining in home and abroad, a new type of water inrush, named Dynamic Water Inrush, is presented. Hard rock in overlying strata, aquifer or water in bed seperation in roof, dynamic instability happening in the hard rock are the main geologic engineering conditions that result in the Dynamic Water Inrush. The three factors causing Dynamic Water Inrush are water source, water-leading channel and dynamic source. And the forming and interaction of the three factors are the inherent mechanism of Dynamic Water Inrush. The scientific definition of Dynamic Water Inrush are presented based on the compasion of Dynamic Water Inrush with general water inrush. And the oritention of further research of Dynamic Water Inrush are also presented in this paper.
Taking the serious water inrush accident due to coal mining under super-thick hard igneous rock in Huaibei Mining Group for example, hydrologic and engineering geology conditions of the water inrush are investigated and tested. Based on comparison to the characteristics of other water inrush accidence due to coal mining in home and abroad, a new type of water inrush, named Dynamic Water Inrush, is presented. Hard rock in overlying strata, aquifer or water in bed seperation in roof, dynamic instability happening in the hard rock are the main geologic engineering conditions that result in the Dynamic Water Inrush. The three factors causing Dynamic Water Inrush are water source, water-leading channel and dynamic source. And the forming and interaction of the three factors are the inherent mechanism of Dynamic Water Inrush. The scientific definition of Dynamic Water Inrush are presented based on the compasion of Dynamic Water Inrush with general water inrush. And the oritention of further research of Dynamic Water Inrush are also presented in this paper.
2008, 16(S1): 451-455.
After studying deformation regularity of monitoring points of old powerhouse deformation body in Shawan hydropower station, it can be concluded that the deformation body features as an integral creep slide, which shows pushing in backyard part and traction in its local frontier part. According to the change in displacement rate, the time-accumulation displacement curve was divided into three sections apparently, and it is presented that the deformation body is stable creeping slowly with a constant deformation rate before August 10, accelerating creep in raising speed with a increasing deformation displacement between August 10 and late September, and deceleration creeping with a slow down deformation rate after October and converging and gradually trending stable in November. After studying the displacement regularity of each monitoring point, it can be reached that the deformable body is induced by unmerited drainage from lock chamber traffic tunnel, rainfall makes an important promotion, and the excavation of new provincial highway has crucial effect on local deformation in deformable body.
After studying deformation regularity of monitoring points of old powerhouse deformation body in Shawan hydropower station, it can be concluded that the deformation body features as an integral creep slide, which shows pushing in backyard part and traction in its local frontier part. According to the change in displacement rate, the time-accumulation displacement curve was divided into three sections apparently, and it is presented that the deformation body is stable creeping slowly with a constant deformation rate before August 10, accelerating creep in raising speed with a increasing deformation displacement between August 10 and late September, and deceleration creeping with a slow down deformation rate after October and converging and gradually trending stable in November. After studying the displacement regularity of each monitoring point, it can be reached that the deformable body is induced by unmerited drainage from lock chamber traffic tunnel, rainfall makes an important promotion, and the excavation of new provincial highway has crucial effect on local deformation in deformable body.
2008, 16(S1): 456-463.
Antaibao open pit mine was the first large-scale joint venture open pit mine, during 20 years, several domestic and foreign research units have carried out same studies on the slope stability. In recent years, because the mode of open-underground mining have implemented in Antaibao open pit mine, it was difficult to ensure the eastern and southeast slope stability and establish the boundary under open-underground mining, which also severely affected the normal production. Trough integrated researches, pointed out that there were two failure modes of the slope under open-underground mining, and that the position of open-off cut under underground mining is the nuclear factor to ensure the slope stability. Firstly proposed to use the vertical height of safe mining between open pit mining and underground mining as criteria, and established the boundary parameter by the criteria, provided basis for ensuring the slope stability under the condition of open-underground mining.
Antaibao open pit mine was the first large-scale joint venture open pit mine, during 20 years, several domestic and foreign research units have carried out same studies on the slope stability. In recent years, because the mode of open-underground mining have implemented in Antaibao open pit mine, it was difficult to ensure the eastern and southeast slope stability and establish the boundary under open-underground mining, which also severely affected the normal production. Trough integrated researches, pointed out that there were two failure modes of the slope under open-underground mining, and that the position of open-off cut under underground mining is the nuclear factor to ensure the slope stability. Firstly proposed to use the vertical height of safe mining between open pit mining and underground mining as criteria, and established the boundary parameter by the criteria, provided basis for ensuring the slope stability under the condition of open-underground mining.
2008, 16(S1): 464-471.
Based on the geographical position and geological environmental conditions of Fuma slope,the basic features was analyzed from three sides,which were periphery of landslide, material structure features of sliding mass and sliding mass,landslide deformation evidence.Then formation-evolution mechanism of Fuma slope can be got. The results can be the geological base to analyze the slope stability and countermeasures.
Based on the geographical position and geological environmental conditions of Fuma slope,the basic features was analyzed from three sides,which were periphery of landslide, material structure features of sliding mass and sliding mass,landslide deformation evidence.Then formation-evolution mechanism of Fuma slope can be got. The results can be the geological base to analyze the slope stability and countermeasures.
2008, 16(S1): 472-476.
Construction period always depends on the complexity of cracked rock slops which leads to twice change of the plan in the treatment of the K81 high slop on the Jinliwen expressway. Because we considered that the cracked rock slop formed as geological genesis, the guiding principle was to solve the stability of the rock slope caused by poor rock integrity in the first change. When we implemented the project and performed the geological investigation and analysis deeply, we found that the cracked rock slop was caused by ancient landslide, which leaded to the second change of the plan about the slop treatment after the slope had been excavated and some parts of the reinforcement project had been done. The geological condition in cracked rock slops is complex, and the cause of cracked rock decides the characteristic of the globe stability, therefore the investigation, analysis of the geological model and the exploration would due to proper plans to eliminate the hidden troubles in disasters.
Construction period always depends on the complexity of cracked rock slops which leads to twice change of the plan in the treatment of the K81 high slop on the Jinliwen expressway. Because we considered that the cracked rock slop formed as geological genesis, the guiding principle was to solve the stability of the rock slope caused by poor rock integrity in the first change. When we implemented the project and performed the geological investigation and analysis deeply, we found that the cracked rock slop was caused by ancient landslide, which leaded to the second change of the plan about the slop treatment after the slope had been excavated and some parts of the reinforcement project had been done. The geological condition in cracked rock slops is complex, and the cause of cracked rock decides the characteristic of the globe stability, therefore the investigation, analysis of the geological model and the exploration would due to proper plans to eliminate the hidden troubles in disasters.
2008, 16(S1): 477-482.
Modern high-tech equipments have more and more strict requests on vibration, in the construction process of a clear workshop, we need to reconstruct parts of non-micro-vibration zone of the workshop into micro-vibration zone for expanding the production lines. In this paper, the finite element model of the clear workshop was established to analysis the micro-vibration problem, which was caused by ground random vibration. The acceleration time series measured on the ground as excitation, the random vibratory response of the workshop structure was analyzed. For three different cases, the vibrations of particular nodes in the structure model were compared, the results indicated that increased pillars could effectively reduce the vibration of the structure, consequently, reasonable proposals for engineering design were put forward.
Modern high-tech equipments have more and more strict requests on vibration, in the construction process of a clear workshop, we need to reconstruct parts of non-micro-vibration zone of the workshop into micro-vibration zone for expanding the production lines. In this paper, the finite element model of the clear workshop was established to analysis the micro-vibration problem, which was caused by ground random vibration. The acceleration time series measured on the ground as excitation, the random vibratory response of the workshop structure was analyzed. For three different cases, the vibrations of particular nodes in the structure model were compared, the results indicated that increased pillars could effectively reduce the vibration of the structure, consequently, reasonable proposals for engineering design were put forward.
2008, 16(S1): 483-486.
The differences of weathering indexes and ranking of rock mass in three national codes were compared firstly. The engineering experiences of weathering evaluation in hydroelectric engineering were summarized. And then according to the characters of basalt in a dam site, the weathering indexes and classification were put forward. The quantitative evaluation of weathering of basalt in the dam site was arrived and the better basis of rock mass quality evaluation was provided.
The differences of weathering indexes and ranking of rock mass in three national codes were compared firstly. The engineering experiences of weathering evaluation in hydroelectric engineering were summarized. And then according to the characters of basalt in a dam site, the weathering indexes and classification were put forward. The quantitative evaluation of weathering of basalt in the dam site was arrived and the better basis of rock mass quality evaluation was provided.
2008, 16(S1): 495-499.
It is a difficult problem that a fault is melt when excavating a slope .So countermeasures and deformation instability is analyzed in this paper . And a project example is given to explain the method in detail .
It is a difficult problem that a fault is melt when excavating a slope .So countermeasures and deformation instability is analyzed in this paper . And a project example is given to explain the method in detail .
2008, 16(S1): 500-505.
Because mechanics character of slope rock mass and stability condition in opencast mine have obvious dynamic character, so it is very difficult to got reliable analysis results by tradition method. Therefore, according to the information of deformation monitoring of slope rock mass in this paper, the technique of slope stability analysis was put forward. In order to analyze dynamically slope stability, some deformation monitoring dots were firstly laid on the slope face. Then, the numeric analysis model which corresponding current exploit status was established based on fact exploit status of the Mine (height, angle and geological structure).and the equivalence parameters model of slope rock mass was identified, based on the least criterion of the difference between monitoring displacements and computation displacements. At last, the appraisement of current slope stability and the forecasting of futurity exploiting slope stability were discussed through analyze equivalent parameters. The applied research of the north side A-A cross section slope of Changba opencast mine was carried through based on the analysis technique which is put forward in this paper. The research results show that the technique can get close results with fact slope stability condition, and can provide a new analysis method for the stability analysis and safety appraisement of high and steep mine slope.
Because mechanics character of slope rock mass and stability condition in opencast mine have obvious dynamic character, so it is very difficult to got reliable analysis results by tradition method. Therefore, according to the information of deformation monitoring of slope rock mass in this paper, the technique of slope stability analysis was put forward. In order to analyze dynamically slope stability, some deformation monitoring dots were firstly laid on the slope face. Then, the numeric analysis model which corresponding current exploit status was established based on fact exploit status of the Mine (height, angle and geological structure).and the equivalence parameters model of slope rock mass was identified, based on the least criterion of the difference between monitoring displacements and computation displacements. At last, the appraisement of current slope stability and the forecasting of futurity exploiting slope stability were discussed through analyze equivalent parameters. The applied research of the north side A-A cross section slope of Changba opencast mine was carried through based on the analysis technique which is put forward in this paper. The research results show that the technique can get close results with fact slope stability condition, and can provide a new analysis method for the stability analysis and safety appraisement of high and steep mine slope.
2008, 16(S1): 506-512.
There are many factors worth serious considerations in the the choice of Supporting Structure that used in Slope. The article expatiated on the multiplicity of influencing factors and by combining engineering case analysed how to choose the forms of supporting structure in Slope.
There are many factors worth serious considerations in the the choice of Supporting Structure that used in Slope. The article expatiated on the multiplicity of influencing factors and by combining engineering case analysed how to choose the forms of supporting structure in Slope.
2008, 16(S1): 513-516.
After the three gorge large dames of the Changjiang River reservoir water, the water level will reach 175meters, and surface average wave height will reach 1meter high. Therefore the wave action cannot be neglected for the stability of the rock slope. Based on the mechanical analysis of the rock mass slopes with a belt of weak intercalated layer acting on the wave, this paper obtains that the accumulation of deformation which causes layers weakening and time are the main factors lead to the rock mass slope fault, and finally the stability Evaluation equation considering time factor of wave action is established.
After the three gorge large dames of the Changjiang River reservoir water, the water level will reach 175meters, and surface average wave height will reach 1meter high. Therefore the wave action cannot be neglected for the stability of the rock slope. Based on the mechanical analysis of the rock mass slopes with a belt of weak intercalated layer acting on the wave, this paper obtains that the accumulation of deformation which causes layers weakening and time are the main factors lead to the rock mass slope fault, and finally the stability Evaluation equation considering time factor of wave action is established.
2008, 16(S1): 517-520.
In this paper, by using the FLAC procedure which is based on the finite difference method, we make a numerical simulation of high rock slope. Through the simulation of the four complex engineering conditions that contains before the slope excavation, after the slope excavation, under the bridge foundation load and under the anchor reinforcement, also considering the bridge foundation load's impact on the slope, We can get the slope displacement's change, the distribution of the slope plastic zone's changes and the change in slope stability factor, and then we can evaluate high rock slope stability. This paper focuses on the bridge foundation load's impact on the slope stability and the compensation impact of the cable reinforcement to the bridge foundation load’s negative effect on the slope stability.
In this paper, by using the FLAC procedure which is based on the finite difference method, we make a numerical simulation of high rock slope. Through the simulation of the four complex engineering conditions that contains before the slope excavation, after the slope excavation, under the bridge foundation load and under the anchor reinforcement, also considering the bridge foundation load's impact on the slope, We can get the slope displacement's change, the distribution of the slope plastic zone's changes and the change in slope stability factor, and then we can evaluate high rock slope stability. This paper focuses on the bridge foundation load's impact on the slope stability and the compensation impact of the cable reinforcement to the bridge foundation load’s negative effect on the slope stability.
2008, 16(S1): 521-524.
This paper basically studies the mechanics properties of the rockmass discontinuity for the especial stress state of the rockmass in the current engineering, analyses the results of the shearing test of rockmass discontinuity under loading and unloading, some laws of the strength property of the rockmass discontinuity are made, and compares them, Then makes some conclusions about the strength property of rockmass discontinuity, and presents a formula about shearing strength of rockmass discontinuity to make up the deficiency of the classical theory.
This paper basically studies the mechanics properties of the rockmass discontinuity for the especial stress state of the rockmass in the current engineering, analyses the results of the shearing test of rockmass discontinuity under loading and unloading, some laws of the strength property of the rockmass discontinuity are made, and compares them, Then makes some conclusions about the strength property of rockmass discontinuity, and presents a formula about shearing strength of rockmass discontinuity to make up the deficiency of the classical theory.
2008, 16(S1): 525-528.
Spandrel tank based in the blasting of rock,the rock stress due to the rapid changes in rock relaxation,unloading, in the superficial form of the relaxation zone,with the thickness determine relaxation of the project is of great significance. In this paper, use of longitudinal wave velocity method,such as relaxation zone thickness, and will do some help for other similar project.
Spandrel tank based in the blasting of rock,the rock stress due to the rapid changes in rock relaxation,unloading, in the superficial form of the relaxation zone,with the thickness determine relaxation of the project is of great significance. In this paper, use of longitudinal wave velocity method,such as relaxation zone thickness, and will do some help for other similar project.
2008, 16(S1): 529-535.
The stability of crown surrounding rock masses of great span underground caverns is important to successfully and safely construct. The crown blocks going against stability of surrounding is prevalent because that the surrounding rock masses of Three Gorge underground powerhouse is heavy jointed and very hard. Adopting working process of information construction geology, the crown blocks incised by uncovering structure plane are fleetly searched and located and their stabilities analyzed by the program (GeneralBlock) of 3D-blocks, it is the guidance to shorting and construction of crown. The investigations to crown blocks show that: 43 movable blocks are revealed, hereinto, 11 blocks is instable and 16 blocks is potentially instable, the measures of reinforcing are implemented in time. The flow and method of the investigation can be consulted by analogous projects.
The stability of crown surrounding rock masses of great span underground caverns is important to successfully and safely construct. The crown blocks going against stability of surrounding is prevalent because that the surrounding rock masses of Three Gorge underground powerhouse is heavy jointed and very hard. Adopting working process of information construction geology, the crown blocks incised by uncovering structure plane are fleetly searched and located and their stabilities analyzed by the program (GeneralBlock) of 3D-blocks, it is the guidance to shorting and construction of crown. The investigations to crown blocks show that: 43 movable blocks are revealed, hereinto, 11 blocks is instable and 16 blocks is potentially instable, the measures of reinforcing are implemented in time. The flow and method of the investigation can be consulted by analogous projects.
2008, 16(S1): 536-541.
After the first impoundment of the Three Gorges Reservoir, the Qianjiangping landslide, which is located in Qingganhe River, a tributary of Yangtze River, slid rapidly and travelled for long distance. Through ring shear tests on the samples taken from the sliding zone of the landslide, the mechanism was clarified. The Shuping landslide shows active deformation after the first impoundment. Its deformation model was analyzed based on the monitoring data for more than three years.
After the first impoundment of the Three Gorges Reservoir, the Qianjiangping landslide, which is located in Qingganhe River, a tributary of Yangtze River, slid rapidly and travelled for long distance. Through ring shear tests on the samples taken from the sliding zone of the landslide, the mechanism was clarified. The Shuping landslide shows active deformation after the first impoundment. Its deformation model was analyzed based on the monitoring data for more than three years.
2008, 16(S1): 542-545.
Tumenzi landslide, located in Jiangjin region of Chongqing city, the creep deformation last ever since 1992, the resent accelerating deformation results in the broken of the road and houses in the sliding mass. Studied on the basement of the characteristics of the geology and deformation of the landslide, then did further research on the deformation mechanism and analyzed the stability of the slope. The research result shows that the landslide is in the stage of wholly creep deformation with partly sliding, the continually heavy rain is the main factor which may results in its broken, now it is in the limit state between unstable and stable, which may collapses entirely along several shear opening.
Tumenzi landslide, located in Jiangjin region of Chongqing city, the creep deformation last ever since 1992, the resent accelerating deformation results in the broken of the road and houses in the sliding mass. Studied on the basement of the characteristics of the geology and deformation of the landslide, then did further research on the deformation mechanism and analyzed the stability of the slope. The research result shows that the landslide is in the stage of wholly creep deformation with partly sliding, the continually heavy rain is the main factor which may results in its broken, now it is in the limit state between unstable and stable, which may collapses entirely along several shear opening.
2008, 16(S1): 546-550.
Basised on the geological survey report,through the analysis of the slope structure and the slope deformation,to evaluate the stability of excavated high slope. By use of rigid limit equilibrium method and RockSlope quantitative calculation, judging damage model and reinforcement measures. Theoretical analysis and monitoring data show that the whole stability of permanent crown yard slope is good, but because of the adverse impact on the structure, Small landslides and rockfall are main types of geological hazards, it should be reinforced.
Basised on the geological survey report,through the analysis of the slope structure and the slope deformation,to evaluate the stability of excavated high slope. By use of rigid limit equilibrium method and RockSlope quantitative calculation, judging damage model and reinforcement measures. Theoretical analysis and monitoring data show that the whole stability of permanent crown yard slope is good, but because of the adverse impact on the structure, Small landslides and rockfall are main types of geological hazards, it should be reinforced.
2008, 16(S1): 551-555.
The dates from conventional water pressure test of Guandi Hydropower Station are analyzed by using R/S method. The results show that Permeability of Rock Mass has self-similarity and satisfies scale-invariance, and reflect that the heterogeneous degrees with depths are the essential characteristic of Rock Permeability. The bigger the hausdorff dimension was, the more the heterogeneity with depths of Rock Permeability was. On the contrary, the weaker the heterogeneity with depths of Rock Permeability was.
The dates from conventional water pressure test of Guandi Hydropower Station are analyzed by using R/S method. The results show that Permeability of Rock Mass has self-similarity and satisfies scale-invariance, and reflect that the heterogeneous degrees with depths are the essential characteristic of Rock Permeability. The bigger the hausdorff dimension was, the more the heterogeneity with depths of Rock Permeability was. On the contrary, the weaker the heterogeneity with depths of Rock Permeability was.
2008, 16(S1): 556-559.
Arch Dam frequently use of the Hydropower Project, and it is strictly requests to the rockmasses quality. The fault zones extensive distribute contact face rockmasses,have its thickness and is impossible to dig out completely. Based on the study of comprehensive deformation modulus on contact face rockmasses quality fault zones compression area of Hydropower Project,associative the massive sound waves data and on-site actual measured data, we can take a quantitative evaluation to the excavated rockmasses quality of contact face,and this study can be a evidence to treating local bad rockmasses of excavated contact face,and will do some help for other similar project.
Arch Dam frequently use of the Hydropower Project, and it is strictly requests to the rockmasses quality. The fault zones extensive distribute contact face rockmasses,have its thickness and is impossible to dig out completely. Based on the study of comprehensive deformation modulus on contact face rockmasses quality fault zones compression area of Hydropower Project,associative the massive sound waves data and on-site actual measured data, we can take a quantitative evaluation to the excavated rockmasses quality of contact face,and this study can be a evidence to treating local bad rockmasses of excavated contact face,and will do some help for other similar project.
2008, 16(S1): 560-564.
Whenshan-Chenshan highway is located in Kemen Port in Lianjiang, Fujian province, surrounding Luoyuan Bay, and there is a high rock slope, with a complicated engineering geological condition, to be crossed in the segment of K5+000~K5+140. There are two sets of dominant structural plane developed in the high slope rock mass, and stability of the slope is influenced by them both. Therefore, it is necessary to evaluate the stability. By Stereographic projection, the stability of the natural slope is analyzed. Furthermore, to approach a reasonable slope ratio for excavation, the method is used again. After the cut slope is excavated, the effect is proved to be perfect.
Whenshan-Chenshan highway is located in Kemen Port in Lianjiang, Fujian province, surrounding Luoyuan Bay, and there is a high rock slope, with a complicated engineering geological condition, to be crossed in the segment of K5+000~K5+140. There are two sets of dominant structural plane developed in the high slope rock mass, and stability of the slope is influenced by them both. Therefore, it is necessary to evaluate the stability. By Stereographic projection, the stability of the natural slope is analyzed. Furthermore, to approach a reasonable slope ratio for excavation, the method is used again. After the cut slope is excavated, the effect is proved to be perfect.
2008, 16(S1): 565-569.
When the mechanism of flow slide of loess landslides is discussed, it can find the residual strength plays a major role. The evaluation of residual strength requires a better understanding of undrained saturated loess behavior. Based on the loess landslide occurred at Gaolou village, Shanxi province, the stress state and the increasing model of pore pressure is discussed under stress-controlled undrained triaxial consolidation experiment. The parameter determining the behavior of loess is discussed. Steady state line of saturated loess is established. This line can be used to distinct whether flow slide will occur after liquefaction of loess. According to the test results,the mechanism of flow slide in Gaolou landslide is analysised.
When the mechanism of flow slide of loess landslides is discussed, it can find the residual strength plays a major role. The evaluation of residual strength requires a better understanding of undrained saturated loess behavior. Based on the loess landslide occurred at Gaolou village, Shanxi province, the stress state and the increasing model of pore pressure is discussed under stress-controlled undrained triaxial consolidation experiment. The parameter determining the behavior of loess is discussed. Steady state line of saturated loess is established. This line can be used to distinct whether flow slide will occur after liquefaction of loess. According to the test results,the mechanism of flow slide in Gaolou landslide is analysised.
2008, 16(S1): 570-573.
Firstly, the Shanxi formation coal seam sections and hydrogeological features were analysed in research coal field. Based on the engineering geological characteristics of the thin bedrocks, the failure of the overburden during coal mining were characterized by applying comprehensive research method combining engineering geological mechanical model test and finite element numerical simulation. The development height of caving zone and water flowing fractured zone of difference thickness of coal seam were calculated under the conditions of thin bedrocks. When the mining thickness was more than 3.5m, the water flowing fractured zone reached the Quaternary bottom aquifer in different degree, and the bottom clay layer appeared fracture. These would have effect on the safety mining. The appropriate measures on prevention and cure of water were submitted purposefully, which has been confirmed by the field tests and assured that no water-intrusion hazard or sand rush would occur.
Firstly, the Shanxi formation coal seam sections and hydrogeological features were analysed in research coal field. Based on the engineering geological characteristics of the thin bedrocks, the failure of the overburden during coal mining were characterized by applying comprehensive research method combining engineering geological mechanical model test and finite element numerical simulation. The development height of caving zone and water flowing fractured zone of difference thickness of coal seam were calculated under the conditions of thin bedrocks. When the mining thickness was more than 3.5m, the water flowing fractured zone reached the Quaternary bottom aquifer in different degree, and the bottom clay layer appeared fracture. These would have effect on the safety mining. The appropriate measures on prevention and cure of water were submitted purposefully, which has been confirmed by the field tests and assured that no water-intrusion hazard or sand rush would occur.
2008, 16(S1): 574-578.
In addition to the formation, lithology and geomorphic features in the Yangjiao landslide area, geological structures often played a key role in landslide formation. Furthermore, the massive slip of landslide was often induced by extreme external force, such as strong earthquake, heavy rainfall, etc. The study on landslide formation mechanism contributed to carry out an objective analysis and evaluation of its stability, providing a scientific basis for decision making to the project construction.
In addition to the formation, lithology and geomorphic features in the Yangjiao landslide area, geological structures often played a key role in landslide formation. Furthermore, the massive slip of landslide was often induced by extreme external force, such as strong earthquake, heavy rainfall, etc. The study on landslide formation mechanism contributed to carry out an objective analysis and evaluation of its stability, providing a scientific basis for decision making to the project construction.
2008, 16(S1): 579-583.
The shear strength parameters of potential slide seam are drawn out by back analysis and experience analogy. The shear strength of slide seam would constantly decline because the water intenerates it. Based on further calculation and analysis, rechoose parameters and work out remainder glide-strength. Complying with the rules of safety, economy and feasibility, according to structural character of rock mass, geometrical nexus of rock stratum occurrence and unfavorable geological condition, the route of the zone divides into three segments whose emphases on treatment or deformation monitoring.
The shear strength parameters of potential slide seam are drawn out by back analysis and experience analogy. The shear strength of slide seam would constantly decline because the water intenerates it. Based on further calculation and analysis, rechoose parameters and work out remainder glide-strength. Complying with the rules of safety, economy and feasibility, according to structural character of rock mass, geometrical nexus of rock stratum occurrence and unfavorable geological condition, the route of the zone divides into three segments whose emphases on treatment or deformation monitoring.
2008, 16(S1): 584-589.
To study the application of the principle and technology of TEM prospecting, the authors designed experiments to detect deep-buried caverns under different landforms (mount, valley, slope with different angles). Under the precondition of similarity, by geometrical scaling and actual physical property simulation, response field results same as or proportional to that of prototype are obtained. The authors studied the design of configurations of model experiments, the preparation of experiment materials, the model building, the data acquiring and processing, and got the response characteristics of spherical and cylindrical targets by different devices (superposition, center, and dipole) under complex terrain conditions. The study can provide the principle and data foundation for identifying spherical or cylindrical objects with low resistivity under uneven land surfaces and evaluating the validity of detecting underground caverns by TEM.
To study the application of the principle and technology of TEM prospecting, the authors designed experiments to detect deep-buried caverns under different landforms (mount, valley, slope with different angles). Under the precondition of similarity, by geometrical scaling and actual physical property simulation, response field results same as or proportional to that of prototype are obtained. The authors studied the design of configurations of model experiments, the preparation of experiment materials, the model building, the data acquiring and processing, and got the response characteristics of spherical and cylindrical targets by different devices (superposition, center, and dipole) under complex terrain conditions. The study can provide the principle and data foundation for identifying spherical or cylindrical objects with low resistivity under uneven land surfaces and evaluating the validity of detecting underground caverns by TEM.
2008, 16(S1): 590-596.
Based on the obtained water retention curves, the relative coefficients of permeability of Shanghai soft soil are predicted. At the same time, a series of tri-axial tests have been carried out for the analyzing of unsaturated strength of Shanghai soft soil. Results show that, the air-entry value for Shanghai soft soil (silty clay、clayey silt ) is about 110~250kPa, the residual suction value is about 10~20Mpa, and both of them decrease with the particle size increasing; the WRC for desorption process of Shanghai soft soil shows clearly in step-phase; for the lower suction range (0~1400 kPa), the water retention curves for Shanghai soft soil(layer 21) show significantly in hysteretic loop; coefficients of permeability of Shanghai soft soil changes nonlinearly with suction(water content), and it decreases with suction increasing(water content decreasing); for lower suction, the tri-axial strength for unsaturated Shanghai soft soil linearly increases with suction, and the tri-axial shear coefficient φb for Shanghai soft soil (layer 4)is 10.6°.
Based on the obtained water retention curves, the relative coefficients of permeability of Shanghai soft soil are predicted. At the same time, a series of tri-axial tests have been carried out for the analyzing of unsaturated strength of Shanghai soft soil. Results show that, the air-entry value for Shanghai soft soil (silty clay、clayey silt ) is about 110~250kPa, the residual suction value is about 10~20Mpa, and both of them decrease with the particle size increasing; the WRC for desorption process of Shanghai soft soil shows clearly in step-phase; for the lower suction range (0~1400 kPa), the water retention curves for Shanghai soft soil(layer 21) show significantly in hysteretic loop; coefficients of permeability of Shanghai soft soil changes nonlinearly with suction(water content), and it decreases with suction increasing(water content decreasing); for lower suction, the tri-axial strength for unsaturated Shanghai soft soil linearly increases with suction, and the tri-axial shear coefficient φb for Shanghai soft soil (layer 4)is 10.6°.
2008, 16(S1): 597-602.
The Shanghai grey clay in raw condition of the fifth layer is in the layer of changing hinge and underground overpast engineering of orbit trafficking station in Shanghai and excavated construction of special deep foundation pit. Experimental study on the deformed localization and the law of the formation of shear bands to this clay is helpful to deeply understand the fundamental mechanical characters of it and provide some significantly directory conclusion for engineering practice. We utilize the plane strain compression apparatus and through the analyzes on the results of consolidated undrained plane strain compression tests on grey clay of the fifth layer in Shanghai, some laws of formation of shear bands and deformed localization are presented quantitatively and the internal relations between formation of shear bands and its yields in clay are discussed.
The Shanghai grey clay in raw condition of the fifth layer is in the layer of changing hinge and underground overpast engineering of orbit trafficking station in Shanghai and excavated construction of special deep foundation pit. Experimental study on the deformed localization and the law of the formation of shear bands to this clay is helpful to deeply understand the fundamental mechanical characters of it and provide some significantly directory conclusion for engineering practice. We utilize the plane strain compression apparatus and through the analyzes on the results of consolidated undrained plane strain compression tests on grey clay of the fifth layer in Shanghai, some laws of formation of shear bands and deformed localization are presented quantitatively and the internal relations between formation of shear bands and its yields in clay are discussed.
2008, 16(S1): 603-607.
At present, engineering disasters caused by expansive soil have attracted worldwide attention. At home and abroad, studies on the improvement of expansive soil have been conducted by many engineers, while literatures on the application of wasted tire rubber powders to improve the strength of the expensive soil are few. In order to increase the use of the recycled resources and reduce the harmful impact of the expensive soil on the engineering, the author conducted a series of explorations to study whether and how the wasted tire rubber powder can improve the expensive soil. In the course of the study, wasted tire rubber powder in different proportion with different water content is mixed with expansive soil to make different ESR( expansive soil-rubber). The result of the test shows that the internal friction angle and the shear strength of the expansive soil increase as the amount of the wasted tire rubber powder increases. And the test also shows that the internal friction dose not have a remarkable change, while the cohesion changes much. This result confirms the assumption that wasted tire rubber powder can improve the expansive soil greatly. This finding opens up a new improving method to reduce the engineering disaster caused by the expensive soil.
At present, engineering disasters caused by expansive soil have attracted worldwide attention. At home and abroad, studies on the improvement of expansive soil have been conducted by many engineers, while literatures on the application of wasted tire rubber powders to improve the strength of the expensive soil are few. In order to increase the use of the recycled resources and reduce the harmful impact of the expensive soil on the engineering, the author conducted a series of explorations to study whether and how the wasted tire rubber powder can improve the expensive soil. In the course of the study, wasted tire rubber powder in different proportion with different water content is mixed with expansive soil to make different ESR( expansive soil-rubber). The result of the test shows that the internal friction angle and the shear strength of the expansive soil increase as the amount of the wasted tire rubber powder increases. And the test also shows that the internal friction dose not have a remarkable change, while the cohesion changes much. This result confirms the assumption that wasted tire rubber powder can improve the expansive soil greatly. This finding opens up a new improving method to reduce the engineering disaster caused by the expensive soil.
2008, 16(S1): 608-611.
The distribution characteristic, survival environment and generation condition of the regional soil in the Yangtze River basin are investigated. It has important significance for the study of distribution and engineering characteristic and discussion of the engineering treatment for the regional soil in the Yangtze River basin.
The distribution characteristic, survival environment and generation condition of the regional soil in the Yangtze River basin are investigated. It has important significance for the study of distribution and engineering characteristic and discussion of the engineering treatment for the regional soil in the Yangtze River basin.
2008, 16(S1): 612-616.
The effects of soft interlayer within some rock sites on seismic response of ground surface are rarely studied. The effects of the depth, thickness and shear velocity of soft interlayer within rock sites on surface peak acceleration are analyzed using one-dimensional equivalent linear method of soil seismic response on the basis of the wave motion model. Primary results show that the intensity of input ground motion doesn’t change the laws of the effects of the depth, thickness and shear velocity of soft interlayer within rock sites on surface peak acceleration, and that the varying laws of surface peak acceration affected by the depth, thickness and shear velocity of soft interlayer are controlled by the comprehensive influences of the three factors.
The effects of soft interlayer within some rock sites on seismic response of ground surface are rarely studied. The effects of the depth, thickness and shear velocity of soft interlayer within rock sites on surface peak acceleration are analyzed using one-dimensional equivalent linear method of soil seismic response on the basis of the wave motion model. Primary results show that the intensity of input ground motion doesn’t change the laws of the effects of the depth, thickness and shear velocity of soft interlayer within rock sites on surface peak acceleration, and that the varying laws of surface peak acceration affected by the depth, thickness and shear velocity of soft interlayer are controlled by the comprehensive influences of the three factors.
THE CURRENT SITUATION AND DEVELOPMENT TREND OF TREATMENT TECHNIQUE FOR SOFT SOIL FOUNDATION IN CHINA
2008, 16(S1): 617-621.
This paper elucidates the current statution and development trend of treatment technique of soft soil foundation in China, and points out the conditions of application and effect of treatment techniques for various soft soil foundation. It foucs on analyzing the characteristics and feasible treatment methods of hydraulic fill on filled recently, then more ever presents suggest that the method of preloading dynamic statics consolidation is mainly direction of treatment technique of soft soil, and Preloading dynamic consolidation make the filling reach ultra concretion lamella,it makes important engineering significance.
This paper elucidates the current statution and development trend of treatment technique of soft soil foundation in China, and points out the conditions of application and effect of treatment techniques for various soft soil foundation. It foucs on analyzing the characteristics and feasible treatment methods of hydraulic fill on filled recently, then more ever presents suggest that the method of preloading dynamic statics consolidation is mainly direction of treatment technique of soft soil, and Preloading dynamic consolidation make the filling reach ultra concretion lamella,it makes important engineering significance.
2008, 16(S1): 622-626.
Road frost boiling is one of the most serious injury in cold region, which affects the road running badly. The development of research on road frost boiling in cold region is reviewed here and the counter measures are introduced. The main problems of the study on road frost boiling in cold region are analyzed and some suggests are provided.
Road frost boiling is one of the most serious injury in cold region, which affects the road running badly. The development of research on road frost boiling in cold region is reviewed here and the counter measures are introduced. The main problems of the study on road frost boiling in cold region are analyzed and some suggests are provided.
2008, 16(S1): 627-633.
Highway crack disease, which is the popular problem all over the world. Therefore, if we don't prevent and cure cracks effectively, or the crack spreading and destroy the pavement even the foundation. The author analyzed the main causes of crack's appearance and development by the detailed investigation and analysis of one high fill and soft subgrade highway. So as to find out the real cases of the crack and serve the data for some methods of maintaining highway in the period of management.
Highway crack disease, which is the popular problem all over the world. Therefore, if we don't prevent and cure cracks effectively, or the crack spreading and destroy the pavement even the foundation. The author analyzed the main causes of crack's appearance and development by the detailed investigation and analysis of one high fill and soft subgrade highway. So as to find out the real cases of the crack and serve the data for some methods of maintaining highway in the period of management.
2008, 16(S1): 634-638.
As urbanization is advanced rapidly, It is of great practical significance to study engineering geological Problems of Projects for how to map out the city's plan and carry out its construction on a rational basis,such significances include coordinating development between construction and environmental protection, effectively controling developing cost. With the technological projects of my instite in the field such as Geotechnical Engineering, Geological Hazards, Hydrogeology and Engineering Geology,Geological Survey,and by collecting and utilizing predecessor's data,the article summarizes the geological problems of projects on special soil in Kunming city.
As urbanization is advanced rapidly, It is of great practical significance to study engineering geological Problems of Projects for how to map out the city's plan and carry out its construction on a rational basis,such significances include coordinating development between construction and environmental protection, effectively controling developing cost. With the technological projects of my instite in the field such as Geotechnical Engineering, Geological Hazards, Hydrogeology and Engineering Geology,Geological Survey,and by collecting and utilizing predecessor's data,the article summarizes the geological problems of projects on special soil in Kunming city.
2008, 16(S1): 639-644.
The geologic disaster of ground subsidence widely happens in the region of soft clays in seashore. The disaster will make the farm damaged, salty water invaded in, the ability of the urban pollution discharge reduced,and also the shipping transportation influenced. So it is very important to research and government it. The main body of the article analyses the produce mechanism of ground subsidence, the development present situation of ground subsidence and the development trend of ground subsidence in the way of researching the geologic disaster of ground subsidence which happened in the region of WENLINGLINGSHINIAN-SONGMEN arterial road, but provide the referenced on the research of ground subsidence.
The geologic disaster of ground subsidence widely happens in the region of soft clays in seashore. The disaster will make the farm damaged, salty water invaded in, the ability of the urban pollution discharge reduced,and also the shipping transportation influenced. So it is very important to research and government it. The main body of the article analyses the produce mechanism of ground subsidence, the development present situation of ground subsidence and the development trend of ground subsidence in the way of researching the geologic disaster of ground subsidence which happened in the region of WENLINGLINGSHINIAN-SONGMEN arterial road, but provide the referenced on the research of ground subsidence.
2008, 16(S1): 645-649.
Soft soil has a notable time effect, understanding thoroughly the behavior and mechanism of creep have significance in describing correctly the engineering behavior of soft soil. Influences to creep which are caused by the factors such as relationship of the strain to time, the deviation stress and strain, the pore-water pressure and time and drainage condition have been analyzed according to the experiment which carries on triaxial creep tests of Zhangzhou soft soil based on different surrounding pressure, different level of deviation stress and different drainage condition. Then parameters were fitted according to the Singh-Mitchell empirical model using the test data, creep equation of Zhangzhou soft soil was given in consolidated-undrained triaxial tests.
Soft soil has a notable time effect, understanding thoroughly the behavior and mechanism of creep have significance in describing correctly the engineering behavior of soft soil. Influences to creep which are caused by the factors such as relationship of the strain to time, the deviation stress and strain, the pore-water pressure and time and drainage condition have been analyzed according to the experiment which carries on triaxial creep tests of Zhangzhou soft soil based on different surrounding pressure, different level of deviation stress and different drainage condition. Then parameters were fitted according to the Singh-Mitchell empirical model using the test data, creep equation of Zhangzhou soft soil was given in consolidated-undrained triaxial tests.
2008, 16(S1): 650-654.
To research the engineering characteristics of Liaoxi loess deeply, using the conventional strain-control triaxial cell to test the loess soil in highway of Fuxin-Chaoyang in west area of Liaoning by consolidated undrained triaxial tests. The indexes of shear strength of loess by are obtained by fitting method. The results show that there is little variability about the indexes of shear strength of Liaoxi loess and two type relationship of stress-strain, that is the type of strain-hardening and the type of strain-softening. On that basis, the stress-strain relationship model is founded and the paper proposes a suitable empirical model about the strain softening curve.
To research the engineering characteristics of Liaoxi loess deeply, using the conventional strain-control triaxial cell to test the loess soil in highway of Fuxin-Chaoyang in west area of Liaoning by consolidated undrained triaxial tests. The indexes of shear strength of loess by are obtained by fitting method. The results show that there is little variability about the indexes of shear strength of Liaoxi loess and two type relationship of stress-strain, that is the type of strain-hardening and the type of strain-softening. On that basis, the stress-strain relationship model is founded and the paper proposes a suitable empirical model about the strain softening curve.
2008, 16(S1): 655-660.
In order to afford the accurate engineering data of rock and soil along the new 750 kV Transmission Lines from east of Lanzhou to east of Yinchuan,an all-sided geotechnical engineering Exploration is needed. The landform,phsiognomy,geologic construct,earthquake and area characteristic of geotechnic is presented along an 193.246 km-long transmission Line in Ningxia area .and the original data of engineering geological properties,liquefaction of soil,causticity of soil, Collapsible Loess and its class is gived . Also some idiographic advise for loess,desert and erode development area foundation disposing in this area.is put forword.
In order to afford the accurate engineering data of rock and soil along the new 750 kV Transmission Lines from east of Lanzhou to east of Yinchuan,an all-sided geotechnical engineering Exploration is needed. The landform,phsiognomy,geologic construct,earthquake and area characteristic of geotechnic is presented along an 193.246 km-long transmission Line in Ningxia area .and the original data of engineering geological properties,liquefaction of soil,causticity of soil, Collapsible Loess and its class is gived . Also some idiographic advise for loess,desert and erode development area foundation disposing in this area.is put forword.
2008, 16(S1): 661-665.
Located in the east of Hangzhou, Xiasha is one of the main economic development zones of the new times when Hangzhou is advancing towards the Qianting River Era from the West Lake Era.The main soil stratums around the 14 meters depth are sandy silts formed by recent alluvial deposit of Qianting River,with special engineering properties and variability.An series of triaxial tests were performed on undisturbed,disturbed and remolded specimens of Hangzhou Xiasha silts. The results of the investigation showed that silt samples are easily disturbed, and their undrained strength cannot be used to predict in situ behavior. The stress-strain-strength of undisturbed specimens exhibit work softening, while that of disturbed specimens exhibit work hardening. In addition, the pore water pressure increases to a peak and then gradually and continuously decreases with strain, and specimens have tendency to dilate during shear . These fingings would provide more knowledge about Xiasha Silt characteristics, and could be used as reference for general engineering.
Located in the east of Hangzhou, Xiasha is one of the main economic development zones of the new times when Hangzhou is advancing towards the Qianting River Era from the West Lake Era.The main soil stratums around the 14 meters depth are sandy silts formed by recent alluvial deposit of Qianting River,with special engineering properties and variability.An series of triaxial tests were performed on undisturbed,disturbed and remolded specimens of Hangzhou Xiasha silts. The results of the investigation showed that silt samples are easily disturbed, and their undrained strength cannot be used to predict in situ behavior. The stress-strain-strength of undisturbed specimens exhibit work softening, while that of disturbed specimens exhibit work hardening. In addition, the pore water pressure increases to a peak and then gradually and continuously decreases with strain, and specimens have tendency to dilate during shear . These fingings would provide more knowledge about Xiasha Silt characteristics, and could be used as reference for general engineering.
2008, 16(S1): 666-672.
Secondary freezing-thawing hazards in permafrost regions Qinghai-Tibet railway roadbed are key of the railway safe use. This paper summarized seven types main secondary freezing-thawing hazards along the permafrost regions Qinghai-Tibet railway roadbed which would impact on railway transportation in future, such as cracking of road shoulder and berm, frost crack of abutment, protection slope and culvert, drumlin and ice sheet, frost heaving and frost mound, thaw lakes, thawing groove and frost weathering etc., after careful survey for the Qinghai-Tibet railway that has been used for about 1.5 years. Via observation of the secondary freezing-thawing hazards, to analyze their character and cause of formation. This will offer to the important reference basis for prevention and cure of the disease of Qinghai-Tibet railway roadbed.
Secondary freezing-thawing hazards in permafrost regions Qinghai-Tibet railway roadbed are key of the railway safe use. This paper summarized seven types main secondary freezing-thawing hazards along the permafrost regions Qinghai-Tibet railway roadbed which would impact on railway transportation in future, such as cracking of road shoulder and berm, frost crack of abutment, protection slope and culvert, drumlin and ice sheet, frost heaving and frost mound, thaw lakes, thawing groove and frost weathering etc., after careful survey for the Qinghai-Tibet railway that has been used for about 1.5 years. Via observation of the secondary freezing-thawing hazards, to analyze their character and cause of formation. This will offer to the important reference basis for prevention and cure of the disease of Qinghai-Tibet railway roadbed.
2008, 16(S1): 673-676.
The type and the basic features of the expansive soil crack are evaluated according to the exploration of the South-to-North water diversion project, and the fissure development at the excavation slope and it's influence to the slope stability are evaluated also in the paper.
The type and the basic features of the expansive soil crack are evaluated according to the exploration of the South-to-North water diversion project, and the fissure development at the excavation slope and it's influence to the slope stability are evaluated also in the paper.
2008, 16(S1): 677-680.
n this paper, based on the laboratory test, analyzed the relationship between the shear strength and plastic index of remolded clay in Shanghai. And also analyzed the relationship between the shear strength and the depth of soil layer .The results indicate that the shear strength and plastic index of the remolded clay has little linear correlation. And with the depth of soil increasing, the angle of internal friction decreases gradually.
n this paper, based on the laboratory test, analyzed the relationship between the shear strength and plastic index of remolded clay in Shanghai. And also analyzed the relationship between the shear strength and the depth of soil layer .The results indicate that the shear strength and plastic index of the remolded clay has little linear correlation. And with the depth of soil increasing, the angle of internal friction decreases gradually.
2008, 16(S1): 681-684.
Based on the consolidation tests of Shanghai clay in undisturbed and reconstituted state, the different compressibility of undisturbed soil and reconstituted soil, as well as coefficient of compressibility and modulus of compressibility are analyzed. The influence of soil structure on the compressibility of shanghai clay is investigated, and tiny behavior of soil is analyzed. The yielding structure strain of shanghai clay is obtained, which is between 100 to 150 kpa, and how it affect coefficient of compressibility and modulus of compressibility is also investigated.
Based on the consolidation tests of Shanghai clay in undisturbed and reconstituted state, the different compressibility of undisturbed soil and reconstituted soil, as well as coefficient of compressibility and modulus of compressibility are analyzed. The influence of soil structure on the compressibility of shanghai clay is investigated, and tiny behavior of soil is analyzed. The yielding structure strain of shanghai clay is obtained, which is between 100 to 150 kpa, and how it affect coefficient of compressibility and modulus of compressibility is also investigated.
2008, 16(S1): 685-690.
The bumping at bridge-head on soft soil roadbed caused the problems of driving safety and degraded normal service of the road. Many treatment methods had been introduced briefly according to the major causes of the bumping at bridge-head. A comparative study had been accomplished between the methods such as vacuum preloading, arc approaching slab, multi-stage approaching slab and the combining method of vacuum preloading and arc approaching slab. All of the treatment effect were drew and the results showed that the combining method of vacuum preloading and the arc approaching slab was most effective to reduce the maximum settlement and the differential settlement.
The bumping at bridge-head on soft soil roadbed caused the problems of driving safety and degraded normal service of the road. Many treatment methods had been introduced briefly according to the major causes of the bumping at bridge-head. A comparative study had been accomplished between the methods such as vacuum preloading, arc approaching slab, multi-stage approaching slab and the combining method of vacuum preloading and arc approaching slab. All of the treatment effect were drew and the results showed that the combining method of vacuum preloading and the arc approaching slab was most effective to reduce the maximum settlement and the differential settlement.
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