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Editor Work2017 Vol. 25, No. Z1
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2017, 25(Z1): 1-6.
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In this paper, the source and connotation of Applied Quaternary was expounded, its development process was reviewed in the round as well. By three examples of hydrological engineering environment, we showed the value of Applied Quaternary research in practical engineering. Based on the current Research Status, we recognize it is necessary to develop the core theory of Applied Quaternary research, that is,Supergenesis Kinetics under human activities disturbance. Moreover, 13 important future research focus were pointed out.
In this paper, the source and connotation of Applied Quaternary was expounded, its development process was reviewed in the round as well. By three examples of hydrological engineering environment, we showed the value of Applied Quaternary research in practical engineering. Based on the current Research Status, we recognize it is necessary to develop the core theory of Applied Quaternary research, that is,Supergenesis Kinetics under human activities disturbance. Moreover, 13 important future research focus were pointed out.
2017, 25(Z1): 7-14.
Based on the on-site inspection of the scenic area of Changyu Dongtian in Wenling CityThe author made an assessment that the engineering geological conditions of Changyu Cavern are generally good. Based on these analysesthrough in-depth study of the ancient method of quarryingit is found that this method contains the ancient engineering science and technology bright spot which accords with the principle of rock mechanics. In additionthe basis of acoustic theory about underground music hall was discussed. All these constitute the scientific value of the large ancient underground caverns in the scenic area.
Based on the on-site inspection of the scenic area of Changyu Dongtian in Wenling CityThe author made an assessment that the engineering geological conditions of Changyu Cavern are generally good. Based on these analysesthrough in-depth study of the ancient method of quarryingit is found that this method contains the ancient engineering science and technology bright spot which accords with the principle of rock mechanics. In additionthe basis of acoustic theory about underground music hall was discussed. All these constitute the scientific value of the large ancient underground caverns in the scenic area.
2017, 25(Z1): 15-25.
A scenic spot in Taizhou, Zhejiang province locates in a mountainous area, the terrain changes sharply, and thus many cliffs stand steeply. According to the field research, there are 8 debris flow gullies lay along a stream flowing in northwestern direction. Although small in size, the longitudinal gradients of these gullies are 485~864,which accumulate potential energy for the outbreak of debris flows. A rainstorm on July, 5, 2017 triggered debris flows in these 8 gullies, 7 of which carried debris, piled up and blocked the tour road. Large amount of debris of No.8 gully rushed in the ticket office, causing a serious loss to the scenic spot. In this paper, a detailed field study was carried out on these gullies, and analyzed the features of them and conditions that would trigger debris flows in these gullies. Taking debris flow in No.8 gully for example, many characteristic parameters of which were calculated, such as the bulk density, density, volume of debris for once outbreak, total volume of debris for once outbreak, etc. Based on these parameters, this paper put forward some preventive countermeasures, which could be a reference to the prevention of other debris flows near this scenic spot.
A scenic spot in Taizhou, Zhejiang province locates in a mountainous area, the terrain changes sharply, and thus many cliffs stand steeply. According to the field research, there are 8 debris flow gullies lay along a stream flowing in northwestern direction. Although small in size, the longitudinal gradients of these gullies are 485~864,which accumulate potential energy for the outbreak of debris flows. A rainstorm on July, 5, 2017 triggered debris flows in these 8 gullies, 7 of which carried debris, piled up and blocked the tour road. Large amount of debris of No.8 gully rushed in the ticket office, causing a serious loss to the scenic spot. In this paper, a detailed field study was carried out on these gullies, and analyzed the features of them and conditions that would trigger debris flows in these gullies. Taking debris flow in No.8 gully for example, many characteristic parameters of which were calculated, such as the bulk density, density, volume of debris for once outbreak, total volume of debris for once outbreak, etc. Based on these parameters, this paper put forward some preventive countermeasures, which could be a reference to the prevention of other debris flows near this scenic spot.
2017, 25(Z1): 26-33.
The Shepan Island, which covers a total area of 19.68km2, is a small island with profound historical ground in the Sanmen bay Shepan ocean in eastern Zhejiang Province. The southern part of the island close to the sea is Linglong Mountain of volcanic detritus of the upper Jurassic, and loose sediment of quaternary that is about hundreds of meters long in the south. On its eastern side, the outcrops of the volcanic eruption were found, sea cliff were formed by the geological effect of the waves. A dark, shiny sea mudflat that is about a few tens of meters wide reveals on the beach after the ebb tide. According to the determination, the amount of selenium in sea mud is high, and the small seafood in sea mud, such as clam, which is used to be caught and eaten, can replenish healthy organic selenium. Riding a wooden seahorse and catching small seafood are two features of tourism development of the Shepan Island slime park. In addition, the agglomerates found in the southeast corner of Linglong Mountain can provide evidence for the direction of the crater, which is of scientific value.
The Shepan Island, which covers a total area of 19.68km2, is a small island with profound historical ground in the Sanmen bay Shepan ocean in eastern Zhejiang Province. The southern part of the island close to the sea is Linglong Mountain of volcanic detritus of the upper Jurassic, and loose sediment of quaternary that is about hundreds of meters long in the south. On its eastern side, the outcrops of the volcanic eruption were found, sea cliff were formed by the geological effect of the waves. A dark, shiny sea mudflat that is about a few tens of meters wide reveals on the beach after the ebb tide. According to the determination, the amount of selenium in sea mud is high, and the small seafood in sea mud, such as clam, which is used to be caught and eaten, can replenish healthy organic selenium. Riding a wooden seahorse and catching small seafood are two features of tourism development of the Shepan Island slime park. In addition, the agglomerates found in the southeast corner of Linglong Mountain can provide evidence for the direction of the crater, which is of scientific value.
2017, 25(Z1): 34-37.
With the continuous development of social science and technology, the development and protection's issues of tourism resource has attracted more and more attention. The columnar jointing in the town of Hunan Quzhou, which scale, scientific has high scientific value and tourism value, is extremely worth researching. This thesis firstly analyzes the structure feature of Jointed column, furthermore it studies the strategy of tourism exploitation.
With the continuous development of social science and technology, the development and protection's issues of tourism resource has attracted more and more attention. The columnar jointing in the town of Hunan Quzhou, which scale, scientific has high scientific value and tourism value, is extremely worth researching. This thesis firstly analyzes the structure feature of Jointed column, furthermore it studies the strategy of tourism exploitation.
2017, 25(Z1): 38-44.
Through the sediment particle size experiment of 38 sample from QTZ1 drilling of lower pleistocene in Wenzhou Oujiang estuary, get the sediment particle size parameters, cumulative frequency curves and cumulative probability curves of the early pleistocene in study area. The frequency distribution curve of grain size is mainly single peak, and there are a small number of hump pseudo-unimodal and bimodal curve. The probability accumulation curve is dominated by coarse grain. The sedimentary environment of the quaternary early pleistocene(1.072-1.778Ma BP)was discussed based on the analysis of the ancient geomagnetic data and the existing geological data in Wenzhou. Analyzing the characteristic of particle size and the results reflect the Wenzhou region Oujiang estuary coastal zone during the early pleistocene sedimentary hydrodynamic condition is relatively low and relatively stable, the sedimentary environment of lower update for fine silt and clay level alluvial-sea environment, local development large-scale transgression.
Through the sediment particle size experiment of 38 sample from QTZ1 drilling of lower pleistocene in Wenzhou Oujiang estuary, get the sediment particle size parameters, cumulative frequency curves and cumulative probability curves of the early pleistocene in study area. The frequency distribution curve of grain size is mainly single peak, and there are a small number of hump pseudo-unimodal and bimodal curve. The probability accumulation curve is dominated by coarse grain. The sedimentary environment of the quaternary early pleistocene(1.072-1.778Ma BP)was discussed based on the analysis of the ancient geomagnetic data and the existing geological data in Wenzhou. Analyzing the characteristic of particle size and the results reflect the Wenzhou region Oujiang estuary coastal zone during the early pleistocene sedimentary hydrodynamic condition is relatively low and relatively stable, the sedimentary environment of lower update for fine silt and clay level alluvial-sea environment, local development large-scale transgression.
2017, 25(Z1): 45-53.
This paper present a systematic study of environmental evolution characteristics in southern suburb of Xi'an area since Holocene. Based on the establishment of the loess-paleosol sedimentary sequence since Holocene in the study areas, analyzing the vicissitudes law of the East Asian winter and summer monsoon, providing the evidence for revealing the interference of human activity on the ancient environment in Xi'an area. In the southern suburb of the Xi'an area Shaolingyuan as example, TFPW-MK mutation test and sliding rank sum test are used to analyze the variation of the magnetic susceptibility sequence and concluded the change trend. The results show that:1)the southern suburbs of Xi'an Shaolingyuan magnetic susceptibility sequence at about 3200a B.P. mutations and it has a high degree of variability.2)the content of the study area of loess pollen also has a greater degree of change, revealing that the ecological conditions of the paleo-environment has been deteriorating. Therefore, it can be used to provide the basis for the improvement of the Loess Plateau by the law of the environmental evolution and human activities revealed in this paper.
This paper present a systematic study of environmental evolution characteristics in southern suburb of Xi'an area since Holocene. Based on the establishment of the loess-paleosol sedimentary sequence since Holocene in the study areas, analyzing the vicissitudes law of the East Asian winter and summer monsoon, providing the evidence for revealing the interference of human activity on the ancient environment in Xi'an area. In the southern suburb of the Xi'an area Shaolingyuan as example, TFPW-MK mutation test and sliding rank sum test are used to analyze the variation of the magnetic susceptibility sequence and concluded the change trend. The results show that:1)the southern suburbs of Xi'an Shaolingyuan magnetic susceptibility sequence at about 3200a B.P. mutations and it has a high degree of variability.2)the content of the study area of loess pollen also has a greater degree of change, revealing that the ecological conditions of the paleo-environment has been deteriorating. Therefore, it can be used to provide the basis for the improvement of the Loess Plateau by the law of the environmental evolution and human activities revealed in this paper.
EXPLORATION AND UNDERSTANDING FOR WATER HAZARD IN BUDDHA BAY OF BAODING MOUNTAIN, DAZU ROCK CARVINGS
2017, 25(Z1): 54-62.
Aiming at the existence of severe seepage disease in Buddha Bay of Baoding Mountain, Dazu Rock Carvings, the technical methods of surface mapping, test boring(trenching),geological radar, high-density resistivity, drilling CT,digital borehole camera and pressure(injection) water test and so on were applied, the detailed exploration and tracking monitoring for engineering geology and hydrogeology conditions of the rock carving zone were carried out by stages, so the structural characteristics and hydrogeological characteristics of rock mass of Buddha Bay were found out, and the rules of development and distribution of fracture seepage network were revealed. On this basis, the in-depth analysis for the relative seepage patterns was conducted by using 3D GIS visualization and numerical simulation, so the scientific rationality of the exploration program was verified and the efficiency and accuracy of exploration was improved effectively. This research can provide a sufficient basis for the control of water hazard in Buddha Bay, and offer reference for geological exploration of similar projects.
Aiming at the existence of severe seepage disease in Buddha Bay of Baoding Mountain, Dazu Rock Carvings, the technical methods of surface mapping, test boring(trenching),geological radar, high-density resistivity, drilling CT,digital borehole camera and pressure(injection) water test and so on were applied, the detailed exploration and tracking monitoring for engineering geology and hydrogeology conditions of the rock carving zone were carried out by stages, so the structural characteristics and hydrogeological characteristics of rock mass of Buddha Bay were found out, and the rules of development and distribution of fracture seepage network were revealed. On this basis, the in-depth analysis for the relative seepage patterns was conducted by using 3D GIS visualization and numerical simulation, so the scientific rationality of the exploration program was verified and the efficiency and accuracy of exploration was improved effectively. This research can provide a sufficient basis for the control of water hazard in Buddha Bay, and offer reference for geological exploration of similar projects.
2017, 25(Z1): 63-67.
Longyou Grottoes are the larege ancient underground buildings that excavated by the ancient Chinese people. It has the precious cultural relic value. This paper discusses the features of environmental temperature distribution based on the monitoring data both inside and outside Longyou Grottoes, which provides scientific basis of the study of weathering of surrounding rock.
Longyou Grottoes are the larege ancient underground buildings that excavated by the ancient Chinese people. It has the precious cultural relic value. This paper discusses the features of environmental temperature distribution based on the monitoring data both inside and outside Longyou Grottoes, which provides scientific basis of the study of weathering of surrounding rock.
2017, 25(Z1): 68-74.
Virtual reality technology is a kind of cross fusion of computer technology which is developed on the basis of multiple disciplines, such as computer graphics, sensor technology, computer simulation display. In this paper, according to the very few applications of the virtual reality technology in ancient cavern protection at present, take wedding festivities night ancient cavern of Yeren Caverns Scenic Spot of Shepan island of Zhejiang province with important cultural relics and tourism value as an example, to virtual reappear the ancient scene of wedding festivities night ancient cavern and the spatial environment existed in history. It provides the basis to the protection and development of the ancient caverns of wedding festivities night ancient cavern, and it's a beneficial attempt for the application of the virtual reality technology in ancient cavern protection.
Virtual reality technology is a kind of cross fusion of computer technology which is developed on the basis of multiple disciplines, such as computer graphics, sensor technology, computer simulation display. In this paper, according to the very few applications of the virtual reality technology in ancient cavern protection at present, take wedding festivities night ancient cavern of Yeren Caverns Scenic Spot of Shepan island of Zhejiang province with important cultural relics and tourism value as an example, to virtual reappear the ancient scene of wedding festivities night ancient cavern and the spatial environment existed in history. It provides the basis to the protection and development of the ancient caverns of wedding festivities night ancient cavern, and it's a beneficial attempt for the application of the virtual reality technology in ancient cavern protection.
2017, 25(Z1): 75-81.
Based on the discrete element method of the Particle flow code(PFC2D),simulate the deformation,failure and slide whole process of the deposit landslide. According to field investigation, the causes and formation mechanism of the Baidian township I landslide are summarized. The landslide is caused by the internal and external geological action, the main reasons is the loosen structure of the deposit, rain infiltration after strong rainfall and form weak slip zone, cause the slope creep and deformation. A series of biaxial tests are simulated to establish the relationship between micro parameters and macro mechanical properties. Then, the landslide geological model is established and the whole process of deformation and failure of the landslide is simulated by softening the strength of slip zone considering rainfall conditions. The progressive failure process of landslide is simulated. The simulation results show that the shear crack concentrated in the slope foot and the tension crack concentrated in the top of the slope, with creep deformation of the slope slowly, cracks scope in the slope toe expanding gradually and the tension crack occurs in the middle part of the slope; the sliding velocity can be divided into four stages:sliding creep deformation,slip acceleration,slip deceleration and slow accumulation. Based on the landslide displacement and finally accumulation state show that Baidian township Ⅰ landslide threatening the safety of Longtan Village primary school and the rural road, the simulation results have an important guiding value for the project management of the landslide.
Based on the discrete element method of the Particle flow code(PFC2D),simulate the deformation,failure and slide whole process of the deposit landslide. According to field investigation, the causes and formation mechanism of the Baidian township I landslide are summarized. The landslide is caused by the internal and external geological action, the main reasons is the loosen structure of the deposit, rain infiltration after strong rainfall and form weak slip zone, cause the slope creep and deformation. A series of biaxial tests are simulated to establish the relationship between micro parameters and macro mechanical properties. Then, the landslide geological model is established and the whole process of deformation and failure of the landslide is simulated by softening the strength of slip zone considering rainfall conditions. The progressive failure process of landslide is simulated. The simulation results show that the shear crack concentrated in the slope foot and the tension crack concentrated in the top of the slope, with creep deformation of the slope slowly, cracks scope in the slope toe expanding gradually and the tension crack occurs in the middle part of the slope; the sliding velocity can be divided into four stages:sliding creep deformation,slip acceleration,slip deceleration and slow accumulation. Based on the landslide displacement and finally accumulation state show that Baidian township Ⅰ landslide threatening the safety of Longtan Village primary school and the rural road, the simulation results have an important guiding value for the project management of the landslide.
2017, 25(Z1): 82-87.
As a new method to obtain geographic information, UAV(unmanned aerial vehicle) has attracted a lot of attention. Compared with professional photogrammetry fixed wing UAV and large multi-rotor UAV,small quad-rotor wing UAV is more flexible, more maneuverable and more economical to survey the topographic of single disaster and micro-region. In allusion to the particularity of the working environment for rockfall survey, this article studied the influence of flight height and the angle of camera to the accuracy of data acquired by mini quadrotor UAV when it's impossible to set GCPs(ground control points) in field to optimize the data. The results indicated that:(1)DJI phantom 3 UAV can improve the horizontal accuracy in 63%,vertical accuracy in 7%when decrease the flight height from 150m to 90m, and improve the horizontal accuracy in15%~69%,vertical accuracy in 6%~9% when keeping the lens vertical. (2)In the context of a rockfall survey case in Shandong province Zibo City, author obtained the topographic data by UAV,then analyzed the 3-D numerical simulation of the rockfall movement utilizing Rockyfor3D program, the result showing the rockfall movement will threat the power grid and road has certain significance for prevention and control work for rockfall disaster.
As a new method to obtain geographic information, UAV(unmanned aerial vehicle) has attracted a lot of attention. Compared with professional photogrammetry fixed wing UAV and large multi-rotor UAV,small quad-rotor wing UAV is more flexible, more maneuverable and more economical to survey the topographic of single disaster and micro-region. In allusion to the particularity of the working environment for rockfall survey, this article studied the influence of flight height and the angle of camera to the accuracy of data acquired by mini quadrotor UAV when it's impossible to set GCPs(ground control points) in field to optimize the data. The results indicated that:(1)DJI phantom 3 UAV can improve the horizontal accuracy in 63%,vertical accuracy in 7%when decrease the flight height from 150m to 90m, and improve the horizontal accuracy in15%~69%,vertical accuracy in 6%~9% when keeping the lens vertical. (2)In the context of a rockfall survey case in Shandong province Zibo City, author obtained the topographic data by UAV,then analyzed the 3-D numerical simulation of the rockfall movement utilizing Rockyfor3D program, the result showing the rockfall movement will threat the power grid and road has certain significance for prevention and control work for rockfall disaster.
2017, 25(Z1): 88-94.
In order to study soil-water characteristic curve(SWCC) of undisturbed lateritic clay in West Zhejiang in full suction range, three suction control or measurement methods are used, including the pressure plate method, filter paper method and saturated salt solution method to measure the water moisture under different suction. The results show that SWCC obtained from different methods can be coincidence with the same suction and SWCC in full range can be measured with the combination of three different methods. SWCC of undisturbed lateritic clay in full range show that the air entry values of clay is very low, only about 20kPa. Furthermore, compared with the typical SWCC of unsaturated clay, the transition section of SWCC of undisturbed lateritic clay is not a straight line but composed by two lines with different slopes, which is caused by the grain group aggregate between lateritic grain mass.
In order to study soil-water characteristic curve(SWCC) of undisturbed lateritic clay in West Zhejiang in full suction range, three suction control or measurement methods are used, including the pressure plate method, filter paper method and saturated salt solution method to measure the water moisture under different suction. The results show that SWCC obtained from different methods can be coincidence with the same suction and SWCC in full range can be measured with the combination of three different methods. SWCC of undisturbed lateritic clay in full range show that the air entry values of clay is very low, only about 20kPa. Furthermore, compared with the typical SWCC of unsaturated clay, the transition section of SWCC of undisturbed lateritic clay is not a straight line but composed by two lines with different slopes, which is caused by the grain group aggregate between lateritic grain mass.
2017, 25(Z1): 95-106.
Regional land subsidence induced by groundwater overdraft has became a global problem. The land subsidence is relatively development in our country especially, North China plain, Fen-Wei Basin and Yangtze River delta. Subsidence preventive was a significant challenge in urban geological. This paper aims to put forward the conception of land subsidence unit based on ideas of systematic land subsidence preventive. It considers that structure, lithology, groundwater system and aquifer structure are based to divide land subsidence units. Three mainly factors are confirmed by analysis main geological conditions and formation mechanism of land subsidence, include division of groundwater system, aquifer system and thickness of compressible layers. The division principle of land subsidence units was proposed mainly based on the three factors. Using Beijing plain as a target area, the twenty units of land subsidence are divided based on spatial analysis platform of GIS.The units of land subsidence are concordant with the status of land subsidence, and generally characteristic of land subsidence are reflected in some extent, which are based on compare and analysis the relationship between subsidence units and subsidence areas. It is proposed that land subsidence units could be applied for investigation, monitoring, study and preventive of land subsidence, then thoroughly develops the study of control mode of subsidence division. It can make more reasonable, accurate and systematic for prevention and control of land subsidence in the future.
Regional land subsidence induced by groundwater overdraft has became a global problem. The land subsidence is relatively development in our country especially, North China plain, Fen-Wei Basin and Yangtze River delta. Subsidence preventive was a significant challenge in urban geological. This paper aims to put forward the conception of land subsidence unit based on ideas of systematic land subsidence preventive. It considers that structure, lithology, groundwater system and aquifer structure are based to divide land subsidence units. Three mainly factors are confirmed by analysis main geological conditions and formation mechanism of land subsidence, include division of groundwater system, aquifer system and thickness of compressible layers. The division principle of land subsidence units was proposed mainly based on the three factors. Using Beijing plain as a target area, the twenty units of land subsidence are divided based on spatial analysis platform of GIS.The units of land subsidence are concordant with the status of land subsidence, and generally characteristic of land subsidence are reflected in some extent, which are based on compare and analysis the relationship between subsidence units and subsidence areas. It is proposed that land subsidence units could be applied for investigation, monitoring, study and preventive of land subsidence, then thoroughly develops the study of control mode of subsidence division. It can make more reasonable, accurate and systematic for prevention and control of land subsidence in the future.
2017, 25(Z1): 107-111.
The author selects a deposit slope of the Hunan Hengyang Nanyue Baidian as the research object. Through analysing the structure characteristics of the particularity of deposit, suggests using image analysis technology to collaborate with field experiment to get the stone content of the deposit. Through image acquisition, image processing, image analysis, data processing and a series of necessary operations to get the block proportion data, then combine with field experiment data to statistic block proportion. The result shows that the principle of image processing technology is reliable and easily to operate date. Combining image processing and field experiments make the geotechnical test results more accurate, and the method can be widely used in the other deposit slope work.
The author selects a deposit slope of the Hunan Hengyang Nanyue Baidian as the research object. Through analysing the structure characteristics of the particularity of deposit, suggests using image analysis technology to collaborate with field experiment to get the stone content of the deposit. Through image acquisition, image processing, image analysis, data processing and a series of necessary operations to get the block proportion data, then combine with field experiment data to statistic block proportion. The result shows that the principle of image processing technology is reliable and easily to operate date. Combining image processing and field experiments make the geotechnical test results more accurate, and the method can be widely used in the other deposit slope work.
2017, 25(Z1): 112-118.
Longyou ancient underground cavern No.23 is measured nondestructive using equipment such as GPS,total station, automatic compensated level. According to the characteristics of the ancient cavern, closed traverse control survey method is used for the plane control survey, closing level line survey method is used for elevation control measurement. Plane dimension size of this cave, elevation size of hole and rock pillars, section size of cave body are detailed surveyed and mapped.3D model of the ancient cavern is build through software such as AUTOCAD Cyclone ANSYS,which provides new ideas for follow-up numerical simulation, for nondestructive protection and repair work.
Longyou ancient underground cavern No.23 is measured nondestructive using equipment such as GPS,total station, automatic compensated level. According to the characteristics of the ancient cavern, closed traverse control survey method is used for the plane control survey, closing level line survey method is used for elevation control measurement. Plane dimension size of this cave, elevation size of hole and rock pillars, section size of cave body are detailed surveyed and mapped.3D model of the ancient cavern is build through software such as AUTOCAD Cyclone ANSYS,which provides new ideas for follow-up numerical simulation, for nondestructive protection and repair work.
2017, 25(Z1): 119-128.
This paper selects Boredao scenic spot in Shenxianju scenic area as the research object, use the uav aerial photography technology to complex terrain modeling. On the basis of the characteristics of topographic features, engineering geological conditions and the destruction of slope rock mass, combine with Flac3D finite difference numerical simulation technology and 3DEC discrete element numerical simulation technology, the whole stability, stress distribution and displacement distribution of rock mass are simulated by Flac3D; the process of deformation and collapse of the same model and the local stability of rock mass is simulated by using 3DEC discrete element numerical simulation. Combined with the results of simulation analysis, the stability of rock mass is evaluated comprehensively to increase the reliability of numerical simulation analysis. The results of numerical simulation show that the stability of rock mass is very low, and the results are basically consistent with the actual survey results. Therefore, it is suggested to avoid the road.
This paper selects Boredao scenic spot in Shenxianju scenic area as the research object, use the uav aerial photography technology to complex terrain modeling. On the basis of the characteristics of topographic features, engineering geological conditions and the destruction of slope rock mass, combine with Flac3D finite difference numerical simulation technology and 3DEC discrete element numerical simulation technology, the whole stability, stress distribution and displacement distribution of rock mass are simulated by Flac3D; the process of deformation and collapse of the same model and the local stability of rock mass is simulated by using 3DEC discrete element numerical simulation. Combined with the results of simulation analysis, the stability of rock mass is evaluated comprehensively to increase the reliability of numerical simulation analysis. The results of numerical simulation show that the stability of rock mass is very low, and the results are basically consistent with the actual survey results. Therefore, it is suggested to avoid the road.
2017, 25(Z1): 129-133.
The maximum dry density and optimal moisture content of soil are key indicators of compression, shear and penetration in earthwork. Based on the Malan loess in Jingyang area, compaction curves of reused soil and non-reused soil are contrasted and analyzed through the indoor standard compaction test, and the paper presents the method of using three-point two-time interpolation function to establish the functional relation between the maximum dry density and the optimum moisture content so as to indicate the reliability of the compaction test results. The research indicates that the optimum water content of Malan loess in Jingyang area is 17.07% and the maximum dry density is 1.735g cm-3. The optimum water content and the maximum dry density of reused soil are 1.762g cm-3 and 16.69%,respectively. Compared with non-reused soil, the maximum dry density increased by 1.56% and the optimal water content decreased by 2.23%.The conclusion obtained by using the three-point two-time interpolation function is basically consistent with the compaction test, which shows the accuracy of the compaction test. The method has the advantages of clear thinking and simple calculation, and has high applicability, which provides a theoretical basis for solving the maximum dry density and the optimal water content.
The maximum dry density and optimal moisture content of soil are key indicators of compression, shear and penetration in earthwork. Based on the Malan loess in Jingyang area, compaction curves of reused soil and non-reused soil are contrasted and analyzed through the indoor standard compaction test, and the paper presents the method of using three-point two-time interpolation function to establish the functional relation between the maximum dry density and the optimum moisture content so as to indicate the reliability of the compaction test results. The research indicates that the optimum water content of Malan loess in Jingyang area is 17.07% and the maximum dry density is 1.735g cm-3. The optimum water content and the maximum dry density of reused soil are 1.762g cm-3 and 16.69%,respectively. Compared with non-reused soil, the maximum dry density increased by 1.56% and the optimal water content decreased by 2.23%.The conclusion obtained by using the three-point two-time interpolation function is basically consistent with the compaction test, which shows the accuracy of the compaction test. The method has the advantages of clear thinking and simple calculation, and has high applicability, which provides a theoretical basis for solving the maximum dry density and the optimal water content.
2017, 25(Z1): 134-138.
For different sedimentary environments, saturated hydraulic conductivity, which is an important hydrogeologic parameter, are quite different in every formations. In some engineering projects, original formation is disturbed, and the groundwater flow may be changed because both high embankment and excavation comprise a new formation. In this way, it is important to conduct the research on the saturated hydraulic conductivity of undisturbed loess and remolded loess. In this study, the samples such as Malan loess and Lishi loess in upper layer were collected from Yan'an new area, and the saturated hydraulic conductivity of both undisturbed loess and remolded loess were examined by conducting indoor routine permeability experiment. The comparison results show that the compactness of undisturbed Malan loess is lower than that of undisturbed Lishi loess, and the saturated hydraulic conductivity of undisturbed Malan loess is about 2~4 times higher than that of Lishi loess. However, there are no significant differences between the saturated hydraulic conductivity of remolded Malan loess and that of remolded Lishi loess, but the saturated hydraulic conductivity of loess significantly decreases by three fifths when the original structures are disturbed. Besides, for the biology holes existing in undisturbed Malan loess, the relationship between saturated hydraulic conductivity and dry density or porosity is not monotony. Whereas, a good linear relation exists between log permeability and porosity or dry density for undisturbed Lishi loess and remolded loess.
For different sedimentary environments, saturated hydraulic conductivity, which is an important hydrogeologic parameter, are quite different in every formations. In some engineering projects, original formation is disturbed, and the groundwater flow may be changed because both high embankment and excavation comprise a new formation. In this way, it is important to conduct the research on the saturated hydraulic conductivity of undisturbed loess and remolded loess. In this study, the samples such as Malan loess and Lishi loess in upper layer were collected from Yan'an new area, and the saturated hydraulic conductivity of both undisturbed loess and remolded loess were examined by conducting indoor routine permeability experiment. The comparison results show that the compactness of undisturbed Malan loess is lower than that of undisturbed Lishi loess, and the saturated hydraulic conductivity of undisturbed Malan loess is about 2~4 times higher than that of Lishi loess. However, there are no significant differences between the saturated hydraulic conductivity of remolded Malan loess and that of remolded Lishi loess, but the saturated hydraulic conductivity of loess significantly decreases by three fifths when the original structures are disturbed. Besides, for the biology holes existing in undisturbed Malan loess, the relationship between saturated hydraulic conductivity and dry density or porosity is not monotony. Whereas, a good linear relation exists between log permeability and porosity or dry density for undisturbed Lishi loess and remolded loess.
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