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Editor Work2010 Vol. 18, No. S1
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The mudstone of Mianxian-Ningqiang area in the southern Shaanxi is mainly composed of clay minerals,which characteristics of high shale content,loose rock structure,weak anti-weathering ability and poor physical and mechanical properties.Especially contact with water the mudstone is rapidly expansion,disintegration and softening in the short time,and is significantly for rock fractures development and rock strength decreased,which is dad for Mian-Ning freeway construction.Based on this analysis,water immersion test of mudstone and water interaction is designed and the following conclusions are obtained in this paper: the mudstone failure is easily occurred in the position of montmorillonite and other unstable mineral and fractures are almost development along the horizontal bedding after soaking.With longer soaking time,the rupture surface is formed as fracture transfixion when fractures developed to certain degree.In the circulatory state of saturated-weathering - saturated,the rock fractures are more development,the mechanical properties are more decreased,the rate of disintegration and softening are more fast and the rock failure are more easy than in the state of always soaking.
The mudstone of Mianxian-Ningqiang area in the southern Shaanxi is mainly composed of clay minerals,which characteristics of high shale content,loose rock structure,weak anti-weathering ability and poor physical and mechanical properties.Especially contact with water the mudstone is rapidly expansion,disintegration and softening in the short time,and is significantly for rock fractures development and rock strength decreased,which is dad for Mian-Ning freeway construction.Based on this analysis,water immersion test of mudstone and water interaction is designed and the following conclusions are obtained in this paper: the mudstone failure is easily occurred in the position of montmorillonite and other unstable mineral and fractures are almost development along the horizontal bedding after soaking.With longer soaking time,the rupture surface is formed as fracture transfixion when fractures developed to certain degree.In the circulatory state of saturated-weathering - saturated,the rock fractures are more development,the mechanical properties are more decreased,the rate of disintegration and softening are more fast and the rock failure are more easy than in the state of always soaking.
2010, 18(S1): 6-10.
Based on the 385groups test data about marine clayey soil (Q4m) in Dalian sea area,this paper established the experiential relationship between the liquidity index (IL) and direct shear test index(cohesion (Cq)、angle of internal friction (q)) about marine clayey soil(Q4m):Cq=10.623 I-1.8114L、q=-3.8289ln(IL)+5.8634.
Based on the 385groups test data about marine clayey soil (Q4m) in Dalian sea area,this paper established the experiential relationship between the liquidity index (IL) and direct shear test index(cohesion (Cq)、angle of internal friction (q)) about marine clayey soil(Q4m):Cq=10.623 I-1.8114L、q=-3.8289ln(IL)+5.8634.
2010, 18(S1): 11-16.
This paper studied on the consolidation characteristics of hydraulic fill soil in shanghai through the model test.Subsidence of hydraulic fill soil from hydraulic filling to full consolidation can be divided into three stages: sedimentary stage,particle contact stage and consolidation stage.The increasing of effective stress consists of rapid growth period and slow growth period.The settlement occurred mainly in the early period of consolidation in which the consolidation settlement was proportional to effective stress; and the drainage condition and load applied on soil had great influence on consolidation characteristics and strength of hydraulic fill soil.Based on three controlled experiments under self-weight consolidation with double drainage,single drainage consolidation with loading and self-weight consolidation with single drainage,respectively,the relationship of consolidation,deformation and settlement were indicated which provided helpful reference to settlement prediction and foundation deformation calculation in hydraulic fill soil areas.
This paper studied on the consolidation characteristics of hydraulic fill soil in shanghai through the model test.Subsidence of hydraulic fill soil from hydraulic filling to full consolidation can be divided into three stages: sedimentary stage,particle contact stage and consolidation stage.The increasing of effective stress consists of rapid growth period and slow growth period.The settlement occurred mainly in the early period of consolidation in which the consolidation settlement was proportional to effective stress; and the drainage condition and load applied on soil had great influence on consolidation characteristics and strength of hydraulic fill soil.Based on three controlled experiments under self-weight consolidation with double drainage,single drainage consolidation with loading and self-weight consolidation with single drainage,respectively,the relationship of consolidation,deformation and settlement were indicated which provided helpful reference to settlement prediction and foundation deformation calculation in hydraulic fill soil areas.
2010, 18(S1): 17-21.
The stress-strain relations of Tianjin soft dredger soil is strain hardening,which can be fitted by kondner hyperbolic curve.Based on this,The paper used four kinds of normalization factors to study stress-strain characteristics of CU test of Tianjin soft dredger soil,and also established the normalized equation.The research indicated that using thses four kinds of normalization factors to carry on normalization,the normalized degree is highest when used (1-3)ulti as normalization factor,when used 3 as normalization factor,the normalized degree is lowest,while used (3)n as normalization factor,n takes 0.55～0.65 appropriately.
The stress-strain relations of Tianjin soft dredger soil is strain hardening,which can be fitted by kondner hyperbolic curve.Based on this,The paper used four kinds of normalization factors to study stress-strain characteristics of CU test of Tianjin soft dredger soil,and also established the normalized equation.The research indicated that using thses four kinds of normalization factors to carry on normalization,the normalized degree is highest when used (1-3)ulti as normalization factor,when used 3 as normalization factor,the normalized degree is lowest,while used (3)n as normalization factor,n takes 0.55～0.65 appropriately.
2010, 18(S1): 22-25.
Exploitation of deep groundwater caused by ground subsidence and earth fissures have become the major cities in North China Geological Hazards.In this paper,sandy soil of groundwater depression cones in North China as the research object.Basis on the test of repeated loading and unloading,and the sandy soil was not only elastic but also plastic; the resilience capacity was a is a variable,Sandy soil resilience change with the times rebound and the size of rebound stress.The results may be referred to in the control of disasters like land subsidence induced by the exploitation of deep groundwater.
Exploitation of deep groundwater caused by ground subsidence and earth fissures have become the major cities in North China Geological Hazards.In this paper,sandy soil of groundwater depression cones in North China as the research object.Basis on the test of repeated loading and unloading,and the sandy soil was not only elastic but also plastic; the resilience capacity was a is a variable,Sandy soil resilience change with the times rebound and the size of rebound stress.The results may be referred to in the control of disasters like land subsidence induced by the exploitation of deep groundwater.
2010, 18(S1): 26-32.
Calcareous sand is a special geotechnical medium developing in ocean which composes more than 50% CaCO3.Compared with silica-sand,it has unexpected engineering mechanical properties due to origin and special fabic.So many researchers were attracted to research into it.This paper summarized the situation and progresses of calcareous sand in home and abroad,and elucidated in detail the resrarches on the concept and distribution region,its mechanical properties,and foundation types in it.Taking constructing runway on one island of Nansha for example,the paper discussed the feasibility of large engineering on coral reef.Furthermore,the author pointed out that researches on the microcosmic mechanism of particle breakage and its influences on mechanical properties of calcareous sand should be strengthened and the corresponding mechanical models should be built.The foundation types in calcareous sand and how to extract the design parameters should pay much more attention.Engineering environment,the structure and mechanical property of rock and soil masses,the stability of coral reef and so on should be made further studies for build large project on Islands.
Calcareous sand is a special geotechnical medium developing in ocean which composes more than 50% CaCO3.Compared with silica-sand,it has unexpected engineering mechanical properties due to origin and special fabic.So many researchers were attracted to research into it.This paper summarized the situation and progresses of calcareous sand in home and abroad,and elucidated in detail the resrarches on the concept and distribution region,its mechanical properties,and foundation types in it.Taking constructing runway on one island of Nansha for example,the paper discussed the feasibility of large engineering on coral reef.Furthermore,the author pointed out that researches on the microcosmic mechanism of particle breakage and its influences on mechanical properties of calcareous sand should be strengthened and the corresponding mechanical models should be built.The foundation types in calcareous sand and how to extract the design parameters should pay much more attention.Engineering environment,the structure and mechanical property of rock and soil masses,the stability of coral reef and so on should be made further studies for build large project on Islands.
2010, 18(S1): 33-36.
We have tested the swelling ratio and swelling pressure of the load direction(overhead direction)of Chengdu clay intact specimen with pure water.And have tested the free swelling ratio using remodeling specimen.We have discussed the expansive level of Chengdu clay based on results of 6 groups of samples,at the same time we have researched into unlimited lateral expansion characteristic through the experiments on load lateral(overhead direction)swelling of Chengdu clay.This paper summarizes the common engineering geologic disasters of Chengdu clay and gives advices on engineering treatment measures.
We have tested the swelling ratio and swelling pressure of the load direction(overhead direction)of Chengdu clay intact specimen with pure water.And have tested the free swelling ratio using remodeling specimen.We have discussed the expansive level of Chengdu clay based on results of 6 groups of samples,at the same time we have researched into unlimited lateral expansion characteristic through the experiments on load lateral(overhead direction)swelling of Chengdu clay.This paper summarizes the common engineering geologic disasters of Chengdu clay and gives advices on engineering treatment measures.
2010, 18(S1): 37-46.
Understanding of geological features are the key issues and difficult problems in the extra-deep and over-length tunnel,Combination the Da Xiangling-Ni bashan extra-deep and over-length tunnel Investigation,this paper Study the use of geological structural damage to study and analyze the geological characteristics of the deep tunnel wall rock.The Da xiangling-Ni bashan deep-buried(1660m)and over-length(94946m in left, 10007m in right)tunnel located in Intersections of three major tectonic system,which are Da xiangling NW-trending tectonic belt,Longmen moantain NE-trending tectonic belt and Chuan-Dian NS-trending tectonic belt,the faults is very developed,Different structural positions,as well as the composite effect of different tectonic systems,causing structural damage characteristics significantly different in different regions.Geological structure damage factor are defined to describe the geological structure damage,mainly by tectonic location and intensity of tectonic deformation influence coefficient,degree of development of secondary faults influence coefficient,degree of development of joint influence coefficient and the degree of development of micro-cracks of rock influence coefficient.Based on the Da xiangling-Ni bashan tunnel geological information analysis and combination with some other tunnels survey data,put forward the structural damage grading and evaluation methods.The tunnel area are divided into strong structural damage zone,secondary strong structural damage zone and weak structural damage zone,and carry detailed research and analysis of the damage characteristics of each zone.Based on structural damage study,can develop the tunnel exploration program,study of tunnel surrounding rock geological characteristics,qualitative analysis of stress field characteristics of the tunnel and rock burst prediction,analysis the water-control structures and qualitative forecast the tunnel water gushing problem.
Understanding of geological features are the key issues and difficult problems in the extra-deep and over-length tunnel,Combination the Da Xiangling-Ni bashan extra-deep and over-length tunnel Investigation,this paper Study the use of geological structural damage to study and analyze the geological characteristics of the deep tunnel wall rock.The Da xiangling-Ni bashan deep-buried(1660m)and over-length(94946m in left, 10007m in right)tunnel located in Intersections of three major tectonic system,which are Da xiangling NW-trending tectonic belt,Longmen moantain NE-trending tectonic belt and Chuan-Dian NS-trending tectonic belt,the faults is very developed,Different structural positions,as well as the composite effect of different tectonic systems,causing structural damage characteristics significantly different in different regions.Geological structure damage factor are defined to describe the geological structure damage,mainly by tectonic location and intensity of tectonic deformation influence coefficient,degree of development of secondary faults influence coefficient,degree of development of joint influence coefficient and the degree of development of micro-cracks of rock influence coefficient.Based on the Da xiangling-Ni bashan tunnel geological information analysis and combination with some other tunnels survey data,put forward the structural damage grading and evaluation methods.The tunnel area are divided into strong structural damage zone,secondary strong structural damage zone and weak structural damage zone,and carry detailed research and analysis of the damage characteristics of each zone.Based on structural damage study,can develop the tunnel exploration program,study of tunnel surrounding rock geological characteristics,qualitative analysis of stress field characteristics of the tunnel and rock burst prediction,analysis the water-control structures and qualitative forecast the tunnel water gushing problem.
2010, 18(S1): 47-52.
The characteristics of surface undulation profiles is an basic properties of rock joint roughness coefficient(JRC).Researching on variation of joint undulation amplitude helps to analyze the scale effects of joint roughness coefficient.In the text,through series of self-developed scale profilograph,measured various sizes of joint undulation amplitude.By statistics and analysis on variation of undulation amplitude with size of rock joint,the results showed that,undulation amplitude exists in scale effects,and there is different roughness coefficient measurement in the same direction but different Position.However,it has the same trend.The variation of medium-scale and large-scale of joint undulation amplitude increases with the size,and it will approach to different definite value with the increasing size.The average statistics of joint undulation amplitude presented good logarithmic function relationship with alternation sizes.
The characteristics of surface undulation profiles is an basic properties of rock joint roughness coefficient(JRC).Researching on variation of joint undulation amplitude helps to analyze the scale effects of joint roughness coefficient.In the text,through series of self-developed scale profilograph,measured various sizes of joint undulation amplitude.By statistics and analysis on variation of undulation amplitude with size of rock joint,the results showed that,undulation amplitude exists in scale effects,and there is different roughness coefficient measurement in the same direction but different Position.However,it has the same trend.The variation of medium-scale and large-scale of joint undulation amplitude increases with the size,and it will approach to different definite value with the increasing size.The average statistics of joint undulation amplitude presented good logarithmic function relationship with alternation sizes.
2010, 18(S1): 53-59.
Middle-lower angle structural plane is one of important geological flaws,analysis on the formation mechanism and physical and mechanical characteristics of middle-lower angle structural plane,which can offer reliable evidence to constructions of projects.Taking a hydropower station for example,engineering geological properties of middle-lower angle structural plane are analyzed in detail.Combing with geological phenomena,geological history and earth stress distribution of dam areas are analyzed to obtain the formation mechanism of middle-lower angle structural plane.The probable failure patterns of dam foundation are proposed,and the limit equilibrium method is applied to analyze its stability.The result indicates that the dam is stable.
Middle-lower angle structural plane is one of important geological flaws,analysis on the formation mechanism and physical and mechanical characteristics of middle-lower angle structural plane,which can offer reliable evidence to constructions of projects.Taking a hydropower station for example,engineering geological properties of middle-lower angle structural plane are analyzed in detail.Combing with geological phenomena,geological history and earth stress distribution of dam areas are analyzed to obtain the formation mechanism of middle-lower angle structural plane.The probable failure patterns of dam foundation are proposed,and the limit equilibrium method is applied to analyze its stability.The result indicates that the dam is stable.
2010, 18(S1): 60-63.
When granite weathering crust is weathered from unweathered rock to residual soil,the pore space which affects the permeability changes from fissure to pore.As the layer is from intense weathered rock to residual soil,the permeability is from strong to weak.As for residual soil confined water,there isnt an aquifuge in it.The confined water head in intense weathered rock is very high.The water flows vertically.The loss of confined water head is increasing as the permeability is decreasing.We can estimate the loss of the confined water head according to Darcys Law.
When granite weathering crust is weathered from unweathered rock to residual soil,the pore space which affects the permeability changes from fissure to pore.As the layer is from intense weathered rock to residual soil,the permeability is from strong to weak.As for residual soil confined water,there isnt an aquifuge in it.The confined water head in intense weathered rock is very high.The water flows vertically.The loss of confined water head is increasing as the permeability is decreasing.We can estimate the loss of the confined water head according to Darcys Law.
2010, 18(S1): 64-70.
Nierji Reservoir is located in the alluvium and diluvium of Q1 with varied thickness.Based on the investigation of downstream of auxiliary dam on the right bank,the laboratory test and field test,we conclude that the permeability law of clay band is different from Darcy Law because of the existence of bound water.The main influence indicators consist of mineral composition,chemical composition,microstructure,specific surface area,granule,etc.On the macro level it shows as clay permeability, I0 and height of capillary rise.
Nierji Reservoir is located in the alluvium and diluvium of Q1 with varied thickness.Based on the investigation of downstream of auxiliary dam on the right bank,the laboratory test and field test,we conclude that the permeability law of clay band is different from Darcy Law because of the existence of bound water.The main influence indicators consist of mineral composition,chemical composition,microstructure,specific surface area,granule,etc.On the macro level it shows as clay permeability, I0 and height of capillary rise.
2010, 18(S1): 71-75.
Through the thin section identification and micro-characters study.Cracked rock mass are mainlyillite clay with shaly structure,thin-layer structure and joints were developed.Through the analysis of regional tectonic features,the regional tectonic process controls the formation of cracked rock mass.Yan Hecheng fault formed fracture network of the region and cracked rock mass after repeated loading-unloading process by extrusion,tension and squeeze and Zi Jing Guan fault,Fang Shan-Ba Bao Shang fault twist action.Rock mass normal unloading and gently dipping structural plane unloading rebound so that rock mass become more cracked.
Through the thin section identification and micro-characters study.Cracked rock mass are mainlyillite clay with shaly structure,thin-layer structure and joints were developed.Through the analysis of regional tectonic features,the regional tectonic process controls the formation of cracked rock mass.Yan Hecheng fault formed fracture network of the region and cracked rock mass after repeated loading-unloading process by extrusion,tension and squeeze and Zi Jing Guan fault,Fang Shan-Ba Bao Shang fault twist action.Rock mass normal unloading and gently dipping structural plane unloading rebound so that rock mass become more cracked.
2010, 18(S1): 76-80.
The 9th floor loess(L9)in Southern Jingyang County is the main object of the study. Triaxial tests are carried out in order to evaluate the shear strength properties of the loess through varying the confining pressure and water content. We get the relationship between water content and slope stability through analyzing the slope stability with different water content. The following conclusions can be reached: ①The decrease of shear strength of L9 loess is mainly controlled by the decrease of cohesion when water content is 5.3% to 12.3%. ②Both cohesion and internal friction angle have a great impact on the decrease of shear strength of L9 loess when water content is 12.3% to 19.3%. ③The decrease of shear strength of L9 loess is mainly controlled by the decrease of internal friction angle when water content is 19.3% to 25%. ④The amount of water content of L9 loess has a direct impact on the stability of the slope for the slope stability factor declines with water content increases. The results can be used in loess slope engineering management,monitoring,especially early prediction of slope safety in southern Jingyang county.
The 9th floor loess(L9)in Southern Jingyang County is the main object of the study. Triaxial tests are carried out in order to evaluate the shear strength properties of the loess through varying the confining pressure and water content. We get the relationship between water content and slope stability through analyzing the slope stability with different water content. The following conclusions can be reached: ①The decrease of shear strength of L9 loess is mainly controlled by the decrease of cohesion when water content is 5.3% to 12.3%. ②Both cohesion and internal friction angle have a great impact on the decrease of shear strength of L9 loess when water content is 12.3% to 19.3%. ③The decrease of shear strength of L9 loess is mainly controlled by the decrease of internal friction angle when water content is 19.3% to 25%. ④The amount of water content of L9 loess has a direct impact on the stability of the slope for the slope stability factor declines with water content increases. The results can be used in loess slope engineering management,monitoring,especially early prediction of slope safety in southern Jingyang county.
2010, 18(S1): 81-87.
There are always some diseases,such as cavity,escapes spatial,crack,leak and so on,in todays mountain tunnel. Common disease detection methods have the problem of bringing about damage to the tunnel and hasnt a wide range of rapid detection. While,ground penetrating radar will be able to solve the above problems better,taking fast non-destructive detection. In order to improve detection efficiency and accurate interpretation of the image,the forward simulation is necessary. Based on finite-difference time-domain(FDTD)method,using the simulation software GprMax,the author take a forward simulation of the cavitys radar image in mountain tunnel,the simulation results and the actual comparison of model fit well,then compare some influence factors,and make some conclusions. It provides the basis for recognition and experience for complex ground penetrating radar images,lay the foundation for the establishment of a number of image recognition database.
There are always some diseases,such as cavity,escapes spatial,crack,leak and so on,in todays mountain tunnel. Common disease detection methods have the problem of bringing about damage to the tunnel and hasnt a wide range of rapid detection. While,ground penetrating radar will be able to solve the above problems better,taking fast non-destructive detection. In order to improve detection efficiency and accurate interpretation of the image,the forward simulation is necessary. Based on finite-difference time-domain(FDTD)method,using the simulation software GprMax,the author take a forward simulation of the cavitys radar image in mountain tunnel,the simulation results and the actual comparison of model fit well,then compare some influence factors,and make some conclusions. It provides the basis for recognition and experience for complex ground penetrating radar images,lay the foundation for the establishment of a number of image recognition database.
2010, 18(S1): 88-92.
The hydrogeological investigations finding that the loose accumulation horizon pore water,weathering fissure water in bedrock and clastic rock fissure water is the major source of gushing.in order to obtain the permeability coefficient of rock mass,in-site tests such as Pumping test,water injection test and water pressure test have been performed.the construction period inflow has been estimated by runoff modulus method,air precipitation supplies method and dewatering method.The patterns of gushing in different strata also been ascertain.it is recommended that The water plugging measure based on shut-off during construction period.
The hydrogeological investigations finding that the loose accumulation horizon pore water,weathering fissure water in bedrock and clastic rock fissure water is the major source of gushing.in order to obtain the permeability coefficient of rock mass,in-site tests such as Pumping test,water injection test and water pressure test have been performed.the construction period inflow has been estimated by runoff modulus method,air precipitation supplies method and dewatering method.The patterns of gushing in different strata also been ascertain.it is recommended that The water plugging measure based on shut-off during construction period.
2010, 18(S1): 93-98.
Numerical simulation is an effective method to prediction the broken rock zone,and the inputting parameters of factors are the key to reliability in numerical prediction.The effect level of factors on surrounding rock and the sensitivity of factors affecting broken rock zone are studied with the measured displacement and thickness of broken rock zone in the roadway of the third mining area at Renlou coal mine in this paper.The results show that some of the increased confining pressure are consumption of re-broken in surrounding rock after a certain positive change.In the actual excavation,the broken rock zone generation is inevitable as the tunnel excavation happening.The thickness of broken rock zone depends on the rock character and rock structure in no tectonic stress field,and the sensitivity of factors affecting broken rock zone from high to low are the strength of surrounding rock,the span of tunnel,the size of tunnel,the confining pressure of tunnel and the condition of support.
Numerical simulation is an effective method to prediction the broken rock zone,and the inputting parameters of factors are the key to reliability in numerical prediction.The effect level of factors on surrounding rock and the sensitivity of factors affecting broken rock zone are studied with the measured displacement and thickness of broken rock zone in the roadway of the third mining area at Renlou coal mine in this paper.The results show that some of the increased confining pressure are consumption of re-broken in surrounding rock after a certain positive change.In the actual excavation,the broken rock zone generation is inevitable as the tunnel excavation happening.The thickness of broken rock zone depends on the rock character and rock structure in no tectonic stress field,and the sensitivity of factors affecting broken rock zone from high to low are the strength of surrounding rock,the span of tunnel,the size of tunnel,the confining pressure of tunnel and the condition of support.
2010, 18(S1): 99-104.
The paper introduces the application of monitoring technology in Zhanongkou Station of Hangzhou metro line 1,focusing on describes the designing,carrying out and effects of the monitoring technology.The monitoring of lateral displacement,axial forces of the supports,underground water level and the settlement of ground and buildings around was conducted.And the arrangement of monitoring point,monitoring frequency and the setting of alarm value were ruled reasonably in order to guide construction and optimize designation.
The paper introduces the application of monitoring technology in Zhanongkou Station of Hangzhou metro line 1,focusing on describes the designing,carrying out and effects of the monitoring technology.The monitoring of lateral displacement,axial forces of the supports,underground water level and the settlement of ground and buildings around was conducted.And the arrangement of monitoring point,monitoring frequency and the setting of alarm value were ruled reasonably in order to guide construction and optimize designation.
2010, 18(S1): 105-108.
The paper introduces the monitoring lateral displacement of foundation pit excavation of a subway station in Hangzhou,and summarizes its changing law,which provides references for the construction.Then a numerical simulation of the lateral displacement of the pit is conducted with FLAC.The simulation results are compared with monitoring results,and the factors which affect the accuracy of numerical simulation are discussed.
The paper introduces the monitoring lateral displacement of foundation pit excavation of a subway station in Hangzhou,and summarizes its changing law,which provides references for the construction.Then a numerical simulation of the lateral displacement of the pit is conducted with FLAC.The simulation results are compared with monitoring results,and the factors which affect the accuracy of numerical simulation are discussed.
2010, 18(S1): 109-114.
The pumping tests on the hydrogeology,including one-drill pumping tests and multi-drill pumping tests,were carried out for the first phase of No. 1 in Ningbo Urban Rail Transit.According to the differences of environment and conditions,the formulas for one-drill,multi-drill pumping and water level recovery,were applied to obtain the permeability coefficients of the main aquifers in the typical sites.In the end,the permeability coefficients of the aquifers along the line were came up with,that put forward the basis for excavation and dewatering of the planned stations.
The pumping tests on the hydrogeology,including one-drill pumping tests and multi-drill pumping tests,were carried out for the first phase of No. 1 in Ningbo Urban Rail Transit.According to the differences of environment and conditions,the formulas for one-drill,multi-drill pumping and water level recovery,were applied to obtain the permeability coefficients of the main aquifers in the typical sites.In the end,the permeability coefficients of the aquifers along the line were came up with,that put forward the basis for excavation and dewatering of the planned stations.
2010, 18(S1): 115-119.
Tunnel construction may lead to ground deformation.So,in the preparation phase,its necessary to analysis the impact of the construction to surrounding buildings.This article taking shield tunnel construction crossing A Building for Beijing metro line 10 phase 2 as an example,conducted a numerical simulation research by FLAC3D.First,the building status is analyzed by measurement date,then,this article analyzed effects of ground settlement caused by shield tunnel construction on the buildings independent foundation based on numerical simulation,and it has predicted the trend of changes in soil-displacement-field and uneven settlement of the independent foundation,simulated the excavation of shield tunnel in different stages,and the dynamic response to the building foundation,forecasting the uneven settlement of foundation independence.This article analysis the construction scheme about isolation piles driving,and proposes an evaluation methodology that can be used by shield tunnel construction crossing independent foundation,when considering the influence of tunnel construction to structure foundation,Should considering the existing deformation and additional deformation caused by tunnel construction.In order to ensure the normal use of building,building deformation must be controlled in standard,in addition,this article can give references to the same kind of shield tunneling in the future.
Tunnel construction may lead to ground deformation.So,in the preparation phase,its necessary to analysis the impact of the construction to surrounding buildings.This article taking shield tunnel construction crossing A Building for Beijing metro line 10 phase 2 as an example,conducted a numerical simulation research by FLAC3D.First,the building status is analyzed by measurement date,then,this article analyzed effects of ground settlement caused by shield tunnel construction on the buildings independent foundation based on numerical simulation,and it has predicted the trend of changes in soil-displacement-field and uneven settlement of the independent foundation,simulated the excavation of shield tunnel in different stages,and the dynamic response to the building foundation,forecasting the uneven settlement of foundation independence.This article analysis the construction scheme about isolation piles driving,and proposes an evaluation methodology that can be used by shield tunnel construction crossing independent foundation,when considering the influence of tunnel construction to structure foundation,Should considering the existing deformation and additional deformation caused by tunnel construction.In order to ensure the normal use of building,building deformation must be controlled in standard,in addition,this article can give references to the same kind of shield tunneling in the future.
2010, 18(S1): 120-125.
In Longyou Caverns,some of which are full filled with water and keeping their integrity for thousand years,Some others of which are not full filled with water and failures occurred in them. Therefor,an idea can be got from it that full filling with water is a key factor making the caverns keep their integrity for thousand years. In order to verify the idea,the chisel imprints inside and outside of the caverns are measured. Qualitative and quantitative analyses are carried out to study the weathering rate of surrounding rock when it is in different environment under or above water table. The comparison results show that when the cavern is full filled with water all the time,the weathering rate of surrounding rock is relatively slower than that of the caverns not full filled with water.Moreover,numerical computation are carried out to compare the stress distribution of surrounding rock and vertical displacements of the roof. The computaion results verify that full filling with water is benefit for the stability of cavern. When the cavern is full filled with water,the amount of zones in tensile stresses and the tensile stress values of surrounding rock are both smaller than that in the cavern of not full filled with water. When the cavern is part full of water,the improvement of stress distribution is not obvious,the vertical displacements of roof are also increased,which are also not benefit for the stability of the caverns. It can be drawn from above studies that full filling with water is the key factor which makes the caverns keeping their integrity for thousand years.
In Longyou Caverns,some of which are full filled with water and keeping their integrity for thousand years,Some others of which are not full filled with water and failures occurred in them. Therefor,an idea can be got from it that full filling with water is a key factor making the caverns keep their integrity for thousand years. In order to verify the idea,the chisel imprints inside and outside of the caverns are measured. Qualitative and quantitative analyses are carried out to study the weathering rate of surrounding rock when it is in different environment under or above water table. The comparison results show that when the cavern is full filled with water all the time,the weathering rate of surrounding rock is relatively slower than that of the caverns not full filled with water.Moreover,numerical computation are carried out to compare the stress distribution of surrounding rock and vertical displacements of the roof. The computaion results verify that full filling with water is benefit for the stability of cavern. When the cavern is full filled with water,the amount of zones in tensile stresses and the tensile stress values of surrounding rock are both smaller than that in the cavern of not full filled with water. When the cavern is part full of water,the improvement of stress distribution is not obvious,the vertical displacements of roof are also increased,which are also not benefit for the stability of the caverns. It can be drawn from above studies that full filling with water is the key factor which makes the caverns keeping their integrity for thousand years.
2010, 18(S1): 126-131.
At present,Tunneling Boring Machines(TBMs)are extensively used to meet the demands for excavation of urban tunnels in Beijing,but many engineering problems were encountered during tunneling because of geological complexity.In this paper,based on the characteristics of the engineering geology and TBM excavations,the engineering geological problems in Beijing were discussed,and the relations between shield TBM excavations and the characteristics of the engineering geology were analyzed,from which TBM excavations should be better understood.
At present,Tunneling Boring Machines(TBMs)are extensively used to meet the demands for excavation of urban tunnels in Beijing,but many engineering problems were encountered during tunneling because of geological complexity.In this paper,based on the characteristics of the engineering geology and TBM excavations,the engineering geological problems in Beijing were discussed,and the relations between shield TBM excavations and the characteristics of the engineering geology were analyzed,from which TBM excavations should be better understood.
2010, 18(S1): 132-137.
Underplanned Mentougou new city located in the SE of Mentougou district,includes Longquan and Yongding two counties and covers an area of 87km2.There is large undermined area of National coalmine corporation distributed.The subsidence deformation induced by the large undermined area is very sensitive to the undergoing plan of the city.The paper studies the distribution of the undermined area,and builds a large numerical simulation model with FLAC3D based on large amount of data of boreholes and maps.The numerical simulation results indicate that the main subsidence deformation induced by the undermined area concentrated at the Tiaoqianfu-Guanting and Yuejiapo-Zhaojiawa,and the maximum subsidence deformation reaches 28mm with limited area.
Underplanned Mentougou new city located in the SE of Mentougou district,includes Longquan and Yongding two counties and covers an area of 87km2.There is large undermined area of National coalmine corporation distributed.The subsidence deformation induced by the large undermined area is very sensitive to the undergoing plan of the city.The paper studies the distribution of the undermined area,and builds a large numerical simulation model with FLAC3D based on large amount of data of boreholes and maps.The numerical simulation results indicate that the main subsidence deformation induced by the undermined area concentrated at the Tiaoqianfu-Guanting and Yuejiapo-Zhaojiawa,and the maximum subsidence deformation reaches 28mm with limited area.
2010, 18(S1): 138-143.
According to the sketch and the actual geological conditions in excavation,room-to-tail transfer engineering geology,geological conditions in excavation,the main engineering geological problems and the tailwater room spray crown profile of cracks introduced factors from the construction,geological factors,stress factors,temperature,relaxation cycle factors,spray protect joints,Shouli Bu equal factors were analyzed and investigated,that the crown parallel to the axial opening cracks in the structure factor,the major stress factors,blasting disturbance and support not due in time for the incentives.Surrounding rock mass destruction and for the stress-control damage-control block combination.
According to the sketch and the actual geological conditions in excavation,room-to-tail transfer engineering geology,geological conditions in excavation,the main engineering geological problems and the tailwater room spray crown profile of cracks introduced factors from the construction,geological factors,stress factors,temperature,relaxation cycle factors,spray protect joints,Shouli Bu equal factors were analyzed and investigated,that the crown parallel to the axial opening cracks in the structure factor,the major stress factors,blasting disturbance and support not due in time for the incentives.Surrounding rock mass destruction and for the stress-control damage-control block combination.
2010, 18(S1): 144-147.
A field vibration test of dynamic consolidation of collapsible soil in a power plant has been statement,analysis shows that: in the collapsible soil,the vibration decreases rapidly near excitation source.And acceleration peak is greater when tamping energy is larger.In addition,the vibration attenuation characteristics have relationship with soil properties,source size,and vibration frequency and so on.Vibration tests can be used to determine the sphere of construction impact.
A field vibration test of dynamic consolidation of collapsible soil in a power plant has been statement,analysis shows that: in the collapsible soil,the vibration decreases rapidly near excitation source.And acceleration peak is greater when tamping energy is larger.In addition,the vibration attenuation characteristics have relationship with soil properties,source size,and vibration frequency and so on.Vibration tests can be used to determine the sphere of construction impact.
ANALYSIS ON SOIL DISPLACEMENT CAUSED BY SOIL COMPACTION EFFECT OF THE PRESTRESSED CONCRETE PIPE PILE
2010, 18(S1): 148-153.
Prestressed pile with a pile of quality assurance and inspection easy,on-site construction is convenient and low cost characteristics,in the coastal areas are widely used in soft soil. Prestressed pile belongs to soil compaction piles,pile driving resulting soil compaction effect,if not handled properly the measures will cause the surrounding environmental problems affecting the quality of finished pile. In this paper,an engineering analysis of soil caused by pile driving horizontal displacement of the measured data obtained pile driving process,the horizontal displacement of soil with the pile driving area,depth and its rural character and larger variation of the difference. Research group piles of soil caused by the displacement of the paper introduces the overlay approach to simplify the estimate of the level of soil displacement and uplift displacement of pile groups is derived during the construction of soil displacement caused by the estimation formula,and with the works carried out experimental comparison,can be used for engineering.
Prestressed pile with a pile of quality assurance and inspection easy,on-site construction is convenient and low cost characteristics,in the coastal areas are widely used in soft soil. Prestressed pile belongs to soil compaction piles,pile driving resulting soil compaction effect,if not handled properly the measures will cause the surrounding environmental problems affecting the quality of finished pile. In this paper,an engineering analysis of soil caused by pile driving horizontal displacement of the measured data obtained pile driving process,the horizontal displacement of soil with the pile driving area,depth and its rural character and larger variation of the difference. Research group piles of soil caused by the displacement of the paper introduces the overlay approach to simplify the estimate of the level of soil displacement and uplift displacement of pile groups is derived during the construction of soil displacement caused by the estimation formula,and with the works carried out experimental comparison,can be used for engineering.
2010, 18(S1): 154-158.
Hongkong-Zhuhai-Macao Bridge includes main construction and connect project.Based on complex geologic investigation of HZM Bridge and multiplex structures of the project,special technical requirement for site investigation and organization is given.And the termination depth of boreholes is double control,strata characters and design needs.According to the construction of Artificial Islands,two marine water pump tests are taken.The SI and geotechnical results show,although there exist soft soil,total weather granite rock,Liquefaction of sand,seismic settlement of the soft soil,shallow gas and other adverse geologic actions,the intact and hard granite rock could be well base or pile end bearing stratum,and the exploration results can satisfy the design need and support the design scheme.At last briefly looks back the preliminary engineering geologic investigation of HZM Bridge.
Hongkong-Zhuhai-Macao Bridge includes main construction and connect project.Based on complex geologic investigation of HZM Bridge and multiplex structures of the project,special technical requirement for site investigation and organization is given.And the termination depth of boreholes is double control,strata characters and design needs.According to the construction of Artificial Islands,two marine water pump tests are taken.The SI and geotechnical results show,although there exist soft soil,total weather granite rock,Liquefaction of sand,seismic settlement of the soft soil,shallow gas and other adverse geologic actions,the intact and hard granite rock could be well base or pile end bearing stratum,and the exploration results can satisfy the design need and support the design scheme.At last briefly looks back the preliminary engineering geologic investigation of HZM Bridge.
2010, 18(S1): 159-165.
Dynamic compaction method is commonly used to strengthen the ground in engineering. This method is widely used to treat other kinds of soil except for silt,and also is appropriate to reinforce granite residual soil in Guangdong. According to the nature of granite residual soil in Guangdong and dynamic compaction test results of treating newly filling granite residual soil from two test area at some area,the technical parameters of dynamic compaction suiting to the nature of granite residual soil are determined,and some construction parameters are analyzed furthermore,and some new viewpoints for analyzing the dynamic compaction construction parameters are proposed too. Meanwhile by way of analyzing the monitoring results combining with test results with some physical mechanics property index,the reinforcement effect is fully appraised,and some conclusions are summed up that different compaction energy or different geotechnical properties at some area will make different effects on improving granite residual soils.
Dynamic compaction method is commonly used to strengthen the ground in engineering. This method is widely used to treat other kinds of soil except for silt,and also is appropriate to reinforce granite residual soil in Guangdong. According to the nature of granite residual soil in Guangdong and dynamic compaction test results of treating newly filling granite residual soil from two test area at some area,the technical parameters of dynamic compaction suiting to the nature of granite residual soil are determined,and some construction parameters are analyzed furthermore,and some new viewpoints for analyzing the dynamic compaction construction parameters are proposed too. Meanwhile by way of analyzing the monitoring results combining with test results with some physical mechanics property index,the reinforcement effect is fully appraised,and some conclusions are summed up that different compaction energy or different geotechnical properties at some area will make different effects on improving granite residual soils.
2010, 18(S1): 166-169.
In Merchants Zhangzhou Development Zone,some factory 2# building uses the isolated foundation,holds the strength level and takes the strong hang rolled-earth fill as the foundation.After building-up,the building is unable to use normally due to the serious differential settlement.The differential reasons of serious uneven settlement of its foundation are analyzed in this paper: The silt inside the cofferdam accumulates and its thickness is different due to cofferdam before filling stones into the sea; The bioturbation capacity on the accumulated silt caused by high-pressure dynamic compaction decreases; In the tideland,The pile is not formed,backfilled stone is disturbed and particle losses due to backfilled stone consolidated by high-pressure rotary jetting.They are main reasons of uneven foundation.
In Merchants Zhangzhou Development Zone,some factory 2# building uses the isolated foundation,holds the strength level and takes the strong hang rolled-earth fill as the foundation.After building-up,the building is unable to use normally due to the serious differential settlement.The differential reasons of serious uneven settlement of its foundation are analyzed in this paper: The silt inside the cofferdam accumulates and its thickness is different due to cofferdam before filling stones into the sea; The bioturbation capacity on the accumulated silt caused by high-pressure dynamic compaction decreases; In the tideland,The pile is not formed,backfilled stone is disturbed and particle losses due to backfilled stone consolidated by high-pressure rotary jetting.They are main reasons of uneven foundation.
2010, 18(S1): 170-173.
Along with the urbanized advancements development,high-rise construction increased,has produced the numerous shape big holes excavated for building foundation,to prevent the hole excavated for building foundation to collapse,to avoid the bad hydrology geology phenomenon,the maintenance construction security,the guarantee hole excavated for building foundation construction quality,the hole excavated for building foundation precipitation construction is a high-rise construction hole excavated for building foundation project essential part,waits for the unceasing research exploration. The article take the theory relation practice as the research technique,first aspect comparative analysis each hole excavated for building foundation precipitation methods and so on shortcoming,applicable scope,based on this,have carried on the analysis emphatically liberally through the related example to the high-rise construction deep hole excavated for building foundation precipitation plans choice application,provides for the related construction work uses for reference.
Along with the urbanized advancements development,high-rise construction increased,has produced the numerous shape big holes excavated for building foundation,to prevent the hole excavated for building foundation to collapse,to avoid the bad hydrology geology phenomenon,the maintenance construction security,the guarantee hole excavated for building foundation construction quality,the hole excavated for building foundation precipitation construction is a high-rise construction hole excavated for building foundation project essential part,waits for the unceasing research exploration. The article take the theory relation practice as the research technique,first aspect comparative analysis each hole excavated for building foundation precipitation methods and so on shortcoming,applicable scope,based on this,have carried on the analysis emphatically liberally through the related example to the high-rise construction deep hole excavated for building foundation precipitation plans choice application,provides for the related construction work uses for reference.
2010, 18(S1): 174-177.
Homogeneity showed in the materials consisting of bank can result in stable and slower variation of geophysical fields.The termite hidden trouble existing inside of bank can destruct the homogeneity,causing the local and considerable variation of geophysical fields if the destruction is in large scale.The abnormal variation can be found through special devices,analyzed and interpreted by skilled and experienced experts,finally the position and buried depth of the termite hidden can then be pinpointed.This paper introduces the geophysical techniques used in termite detection and investigation,and shows the availability of the methods and gives the precaution in field actual practice with some successfully detecting cases.
Homogeneity showed in the materials consisting of bank can result in stable and slower variation of geophysical fields.The termite hidden trouble existing inside of bank can destruct the homogeneity,causing the local and considerable variation of geophysical fields if the destruction is in large scale.The abnormal variation can be found through special devices,analyzed and interpreted by skilled and experienced experts,finally the position and buried depth of the termite hidden can then be pinpointed.This paper introduces the geophysical techniques used in termite detection and investigation,and shows the availability of the methods and gives the precaution in field actual practice with some successfully detecting cases.
2010, 18(S1): 178-181.
With the measured data on the soft soil subgrade settlement,the curve fitting methods,hyperbolic method,exponential curve method and poisson-curve method,were Respectively taken to fit and forecast the soft soil subgrade settlement in Yangtze River floodplain,which were treated by the vacuum preloading.The results show that the exponential curve method is the best way to calculate and estimate the settlement.More importantly,the exponential curve method can be used to forecast the soft soil subgrade settlement and to guide the subgrade construction.
With the measured data on the soft soil subgrade settlement,the curve fitting methods,hyperbolic method,exponential curve method and poisson-curve method,were Respectively taken to fit and forecast the soft soil subgrade settlement in Yangtze River floodplain,which were treated by the vacuum preloading.The results show that the exponential curve method is the best way to calculate and estimate the settlement.More importantly,the exponential curve method can be used to forecast the soft soil subgrade settlement and to guide the subgrade construction.
2010, 18(S1): 182-189.
Based on the project about the soft-foundation treatment of Baian interchange,Gaofu road,the methods of design and construction monitoring program that are applied to reinforce soft-foundation with sand bag well are introduced systematically.The monitoring results of settlement indicate that the increase of preloading height can significantly effect the increase of soft-foundation consolidation and settlement.the settlement rate is greater at the beginning of loading and medium-term of loading,the settlement rate reduce obviously at the later-term of loading and the time of preloading,so strictly control the size of rating loading and settlement rate are very important at the beginning of loading and medium-term of loading.Sand bag well is applied to soft foundation reinforcement of overpass renovation and expansion section in road widening project can gain good reinforcement result and economic benefits,the further application is valued.
Based on the project about the soft-foundation treatment of Baian interchange,Gaofu road,the methods of design and construction monitoring program that are applied to reinforce soft-foundation with sand bag well are introduced systematically.The monitoring results of settlement indicate that the increase of preloading height can significantly effect the increase of soft-foundation consolidation and settlement.the settlement rate is greater at the beginning of loading and medium-term of loading,the settlement rate reduce obviously at the later-term of loading and the time of preloading,so strictly control the size of rating loading and settlement rate are very important at the beginning of loading and medium-term of loading.Sand bag well is applied to soft foundation reinforcement of overpass renovation and expansion section in road widening project can gain good reinforcement result and economic benefits,the further application is valued.
2010, 18(S1): 190-194.
In recent years,top-down constrction method has become popular in construction of deep foundation pits.But in the region of soil-rock dualistic structure,successful cases of design and construction experiments of this kind of construction are rarely seen.In this paper,the deep foundation pit near Donghai Road was taken as an example to introduce the construction process and main construction methods of top-down construction method with bored pile supporting pattern in a typical region of soil-rock dualistic structure like Qingdao,when there are soil and rock field in the excavate effected extent.The Plaxis finite element software was applied to simulate soil excavation in order to analyze the effect of deformation of the supporting construction influenced by the depth of soil excavate and tney were stressed analysed to disscuss the feasibility of jump-layer excavation and the influence to the construction process.
In recent years,top-down constrction method has become popular in construction of deep foundation pits.But in the region of soil-rock dualistic structure,successful cases of design and construction experiments of this kind of construction are rarely seen.In this paper,the deep foundation pit near Donghai Road was taken as an example to introduce the construction process and main construction methods of top-down construction method with bored pile supporting pattern in a typical region of soil-rock dualistic structure like Qingdao,when there are soil and rock field in the excavate effected extent.The Plaxis finite element software was applied to simulate soil excavation in order to analyze the effect of deformation of the supporting construction influenced by the depth of soil excavate and tney were stressed analysed to disscuss the feasibility of jump-layer excavation and the influence to the construction process.
2010, 18(S1): 195-198.
The author obtained the corresponding relation of rayleigh wave velocity and dynamic compaction based on the profound analysis of the test data after the transient ralyleigh wave test(four mouths after dynamic compaction)on the earth-filled(silty clay used as filled material)dynamic compaction test area.The results showed that in the silty clay used as filled materiall foundation,excess pore water pressure dissipated with increasing dynamic compaction; bearing capacity of foundation increased obviously in the 26d after dynamic compaction; Subsequently,increased speed was slow and tended to be stable 107d after dynamic compaction.
The author obtained the corresponding relation of rayleigh wave velocity and dynamic compaction based on the profound analysis of the test data after the transient ralyleigh wave test(four mouths after dynamic compaction)on the earth-filled(silty clay used as filled material)dynamic compaction test area.The results showed that in the silty clay used as filled materiall foundation,excess pore water pressure dissipated with increasing dynamic compaction; bearing capacity of foundation increased obviously in the 26d after dynamic compaction; Subsequently,increased speed was slow and tended to be stable 107d after dynamic compaction.
2010, 18(S1): 199-203.
Taking the slope of A Engineer for example,the dynamic response and failure mechanism of slope rock mass under seismic loading are simulated by FLAC2D.The time-history curve of artificially synthetic acceleration is used.The following results are obtained: under the seismic dynamic load,the side slope could form a large deformation(greater than 3.0m),the plastic zone is distributed between the capping and the interface of the bedrock,the rock and soil of the interface can form a plastic collapse,causing a long-distance landslide,so the comprehensive control measures must be taken.This conclusion has important application value for the selection and construction of the repository.
Taking the slope of A Engineer for example,the dynamic response and failure mechanism of slope rock mass under seismic loading are simulated by FLAC2D.The time-history curve of artificially synthetic acceleration is used.The following results are obtained: under the seismic dynamic load,the side slope could form a large deformation(greater than 3.0m),the plastic zone is distributed between the capping and the interface of the bedrock,the rock and soil of the interface can form a plastic collapse,causing a long-distance landslide,so the comprehensive control measures must be taken.This conclusion has important application value for the selection and construction of the repository.
2010, 18(S1): 204-209.
Peak construction of large buildings in major geotechnical problems is the site stability problems,in this paper,an example of a site along the sloping level of the whole existence of sliding,sliding along the crack and local levels,covering layer of weathered rock block slide,rock collapse and surface rock,stone rolled down so dangerous form of damage,through laboratory and field tests to obtain the structural plane shear strength parameters,slope stability on the top of the conventional method and the finite element method for the quantitative assessment of the overall site stability obtained and meet the requirements of local stability of the conclusions of collapse and dangerous rock on the rock rolling stone risk taking shotcrete support measures,the experience gained in this project has a guide for similar projects.
Peak construction of large buildings in major geotechnical problems is the site stability problems,in this paper,an example of a site along the sloping level of the whole existence of sliding,sliding along the crack and local levels,covering layer of weathered rock block slide,rock collapse and surface rock,stone rolled down so dangerous form of damage,through laboratory and field tests to obtain the structural plane shear strength parameters,slope stability on the top of the conventional method and the finite element method for the quantitative assessment of the overall site stability obtained and meet the requirements of local stability of the conclusions of collapse and dangerous rock on the rock rolling stone risk taking shotcrete support measures,the experience gained in this project has a guide for similar projects.
2010, 18(S1): 210-213.
Slope of a project for the medium soil slope,similar to arc-shaped,divided into four landslide slip surface,with the exception of a slip surface was edge,other edge of the secondary slide surface after the fall of the bandwidth 3～8m range primary slip direction 240,for the Towed landslide.The main reason is the excavation slope instability and the impact of heavy rain,followed by support and drainage measures are not in place.Research shows that before the landslide damage,low coefficient of stability,in an unstable state,the impact of rainfall,slope vulnerable to instability.
Slope of a project for the medium soil slope,similar to arc-shaped,divided into four landslide slip surface,with the exception of a slip surface was edge,other edge of the secondary slide surface after the fall of the bandwidth 3～8m range primary slip direction 240,for the Towed landslide.The main reason is the excavation slope instability and the impact of heavy rain,followed by support and drainage measures are not in place.Research shows that before the landslide damage,low coefficient of stability,in an unstable state,the impact of rainfall,slope vulnerable to instability.
2010, 18(S1): 220-228.
Geological conditions of tunnel are always highly changing and complex,as to ensure the safety and high efficiency in the construction.Its very necessary and importantly to do the predictions of bad natural geological bodies in the construction period.TSP as one of Amberg Measuring Technique corporation s advanced product.Its a geological forecast system specifically design for the long tunnel geological prediction.Compared with other prediction method,from the data collection,processing to interpretation and evaluation are all highly intelligent.In this paper,TSP principle,features,technology development,TSPs problems,etc.were systematically explained.Finally,gave a brief summary on Tunnel Seismic Prediction.Wish to promote TSP application in tunnel construction.
Geological conditions of tunnel are always highly changing and complex,as to ensure the safety and high efficiency in the construction.Its very necessary and importantly to do the predictions of bad natural geological bodies in the construction period.TSP as one of Amberg Measuring Technique corporation s advanced product.Its a geological forecast system specifically design for the long tunnel geological prediction.Compared with other prediction method,from the data collection,processing to interpretation and evaluation are all highly intelligent.In this paper,TSP principle,features,technology development,TSPs problems,etc.were systematically explained.Finally,gave a brief summary on Tunnel Seismic Prediction.Wish to promote TSP application in tunnel construction.
2010, 18(S1): 229-233.
Based on the fact that the explanation of image acquired from Ground Penetrating Radar(GPR)is far from an easy job,a model test was carried out.First a physical model of mountain highway tunnel lining was built.Then a test was carried out using ground penetrating radar to simulate detecting steel reinforcement that embedded in final lining along the tunnel longitudinal direction.After data acquisition stage,a preprocessing procedure including Removing DC Component,Dewowing,Removing Global Background and Trimming Data Matrix was implemented on the raw data,in order to improve signal-to-noise ratio.Data that after preprocessing was divided into block matrices with an overlapping rate of 50 percent to make data proper for Artificial Neural Networks.Then they were used for training and testing the already established BP network.The test indicated that the first layer of steel reinforcement in the second tunnel lining can be effectively recognized with this method.
Based on the fact that the explanation of image acquired from Ground Penetrating Radar(GPR)is far from an easy job,a model test was carried out.First a physical model of mountain highway tunnel lining was built.Then a test was carried out using ground penetrating radar to simulate detecting steel reinforcement that embedded in final lining along the tunnel longitudinal direction.After data acquisition stage,a preprocessing procedure including Removing DC Component,Dewowing,Removing Global Background and Trimming Data Matrix was implemented on the raw data,in order to improve signal-to-noise ratio.Data that after preprocessing was divided into block matrices with an overlapping rate of 50 percent to make data proper for Artificial Neural Networks.Then they were used for training and testing the already established BP network.The test indicated that the first layer of steel reinforcement in the second tunnel lining can be effectively recognized with this method.
2010, 18(S1): 234-237.
According to the propagation characteristics of seismic wave in different media area,pseudo-spectral method is used to process and analyze the seismic wave record from the tunnel face.The results show that the migration profile of the reverse-time depth migration can be more accurately to identify the location of structural plane in front of tunnel face.It can provide the basis for adverse geological conditions in early prediction in front of tunnel face to ensure the reasonable and safe tunnel excavation.
According to the propagation characteristics of seismic wave in different media area,pseudo-spectral method is used to process and analyze the seismic wave record from the tunnel face.The results show that the migration profile of the reverse-time depth migration can be more accurately to identify the location of structural plane in front of tunnel face.It can provide the basis for adverse geological conditions in early prediction in front of tunnel face to ensure the reasonable and safe tunnel excavation.
2010, 18(S1): 238-243.
Combined profiling method and direct current electric sounding method have the character of relative obvious abnormal electrical and high resolution in prospecting stratum and lithology electrical changes,tracking the tectonic research area etc.Applicaton result indicates that these two methods could do better in distinguishing containing mineral rock stratum based on limestone,siliceous rocks containing rich mineral have a high resistivity and low polarity.The engineering examples prove the feasibility synthesize combined profiling method and direct current electric sounding method in containing mineral stratum exploration.
Combined profiling method and direct current electric sounding method have the character of relative obvious abnormal electrical and high resolution in prospecting stratum and lithology electrical changes,tracking the tectonic research area etc.Applicaton result indicates that these two methods could do better in distinguishing containing mineral rock stratum based on limestone,siliceous rocks containing rich mineral have a high resistivity and low polarity.The engineering examples prove the feasibility synthesize combined profiling method and direct current electric sounding method in containing mineral stratum exploration.
2010, 18(S1): 244-248.
Containing water structure and metal mineralization characteristic of different geomorphic units and rock stratum performance different abnormal apparent resistivity feature in sounding section.Combinning derivative Index and the annormal electronic parameters of vertical electrical sounding bisect,the underground containing water strtum and water enrichment condition could be inferred.Engineering examples validation indicate this rearch method is a feasible water detection mthod in mountain area.
Containing water structure and metal mineralization characteristic of different geomorphic units and rock stratum performance different abnormal apparent resistivity feature in sounding section.Combinning derivative Index and the annormal electronic parameters of vertical electrical sounding bisect,the underground containing water strtum and water enrichment condition could be inferred.Engineering examples validation indicate this rearch method is a feasible water detection mthod in mountain area.
2010, 18(S1): 249-252.
Transient Rayleigh wave exploration technique is a new type of seismic exploration method.It stimulates and receives the spread speed of different frequencies of Rayleigh wave to detect the physical and mechanical properties of rock from different depth or distance and provides the basis for understanding the rock properties.This article invitigates the basic principle of transient Rayleigh wave and the method of data interpretation based on the engineering example,and utilizes the frequency disperse curve of Rayleigh wave for layering of shallow layer,determines for the potential sliding surface.
Transient Rayleigh wave exploration technique is a new type of seismic exploration method.It stimulates and receives the spread speed of different frequencies of Rayleigh wave to detect the physical and mechanical properties of rock from different depth or distance and provides the basis for understanding the rock properties.This article invitigates the basic principle of transient Rayleigh wave and the method of data interpretation based on the engineering example,and utilizes the frequency disperse curve of Rayleigh wave for layering of shallow layer,determines for the potential sliding surface.
2010, 18(S1): 253-257.
The basic theory of the geology prediction technology fitting for TBM was introduced with its developing process.The technology was used in the double-shielded TBM construction tunnel first time.Accurate prediction was given for Geological anomaly of the work face.The effect was well by using the above prediction technology in TBM construction tunnel in the transfer project Yin Hong Ji Shi.
The basic theory of the geology prediction technology fitting for TBM was introduced with its developing process.The technology was used in the double-shielded TBM construction tunnel first time.Accurate prediction was given for Geological anomaly of the work face.The effect was well by using the above prediction technology in TBM construction tunnel in the transfer project Yin Hong Ji Shi.
2010, 18(S1): 258-262.
Through in-situ test,this paper validated that the vibro-replacement stone column can be used to reinforce the loess-like soil foundation.The test was carried out on the loess-like soil foundation of Qi-lu petrochemical refinery,and it was found that strength of the soil between piles after vibroflotation is not higher than that of before the vibroflotation.So it is concluded that vibroflotation method can improve the ground bearing capacity of loess-like soil foundation under certain conditions,working current of pile driving can be manipulated to make piles with different pile diameters which can make the foundation strength more uniformity.However,the ground bearing capacity can only be increased by 50% by the large-scale vibroflotation devices with the power of 75 kW,so it is only can be used under certain conditions or while no better choice can be made.
Through in-situ test,this paper validated that the vibro-replacement stone column can be used to reinforce the loess-like soil foundation.The test was carried out on the loess-like soil foundation of Qi-lu petrochemical refinery,and it was found that strength of the soil between piles after vibroflotation is not higher than that of before the vibroflotation.So it is concluded that vibroflotation method can improve the ground bearing capacity of loess-like soil foundation under certain conditions,working current of pile driving can be manipulated to make piles with different pile diameters which can make the foundation strength more uniformity.However,the ground bearing capacity can only be increased by 50% by the large-scale vibroflotation devices with the power of 75 kW,so it is only can be used under certain conditions or while no better choice can be made.
2010, 18(S1): 263-267.
Use of reinforced soil technology is of great significance for Western China to reduce the land occupation of high embankment.With the increase of the fill height,the strength and extensibility of the reinforcement,as well as the analysis method is facing challenges.In this paper,the author studied the principle of stability analysis of reinforced slope,discussed the advantages and disadvantages of different approaches to simulating the effect of reinforcement by finite element method(FEM),focusing on the equivalent additional stress method and its improvement.The author put forward the calculation method of strain ratio coefficient,which makes the method being still feasible in the case of incompatible deformation occurs between reinforcement and soil.In addition,the author discussed other key issues involved in the high reinforced slope.
Use of reinforced soil technology is of great significance for Western China to reduce the land occupation of high embankment.With the increase of the fill height,the strength and extensibility of the reinforcement,as well as the analysis method is facing challenges.In this paper,the author studied the principle of stability analysis of reinforced slope,discussed the advantages and disadvantages of different approaches to simulating the effect of reinforcement by finite element method(FEM),focusing on the equivalent additional stress method and its improvement.The author put forward the calculation method of strain ratio coefficient,which makes the method being still feasible in the case of incompatible deformation occurs between reinforcement and soil.In addition,the author discussed other key issues involved in the high reinforced slope.
2010, 18(S1): 268-273.
There is the replaced-backfilling clay treatment test region,from SY0+208～SY0+268,one part of the Luwangfen test Region of middle-route of South-to-North Water Division Project. , in which the excavated heavy silt loam is dealt as the replace-backfilling clay,then is used to reinforce the swelling slope by vibration bumping roller.During the compaction test,the construction technology and related control standard of replaced-backfilling clay treatment is studied.It is proved that the application of this treatment to reinforce the swelling slope,which is provided as the reference for the treatment of similar slope in the middle-route of South-to-North Water Division Project.
There is the replaced-backfilling clay treatment test region,from SY0+208～SY0+268,one part of the Luwangfen test Region of middle-route of South-to-North Water Division Project. , in which the excavated heavy silt loam is dealt as the replace-backfilling clay,then is used to reinforce the swelling slope by vibration bumping roller.During the compaction test,the construction technology and related control standard of replaced-backfilling clay treatment is studied.It is proved that the application of this treatment to reinforce the swelling slope,which is provided as the reference for the treatment of similar slope in the middle-route of South-to-North Water Division Project.
2010, 18(S1): 274-280.
Base on general three dimension nonlinear numerical simulation software,mechanism of composite soil-nail retaining structures in foundation-pit engineering are analyzed in this paper.Research contents include whole construction process simulation of excavation by steps,soil nailing installation and panel manufacture etc.By the comparison of mechanical characteristics among the pure soil-nail retaining support,pre-stressed anchor composite soil-nail support and pre-reinforced micro pile composite soil-nail support in the same engineering condition,tension distribution range of soil layer,bottom heaving in the pit and axial force distribution along nail etc.are analyzed.The action mechanism and working performance of soil-nail retaining support are also systematically studied and theoretical basis can be provided in optimal design,popularization and application.
Base on general three dimension nonlinear numerical simulation software,mechanism of composite soil-nail retaining structures in foundation-pit engineering are analyzed in this paper.Research contents include whole construction process simulation of excavation by steps,soil nailing installation and panel manufacture etc.By the comparison of mechanical characteristics among the pure soil-nail retaining support,pre-stressed anchor composite soil-nail support and pre-reinforced micro pile composite soil-nail support in the same engineering condition,tension distribution range of soil layer,bottom heaving in the pit and axial force distribution along nail etc.are analyzed.The action mechanism and working performance of soil-nail retaining support are also systematically studied and theoretical basis can be provided in optimal design,popularization and application.
2010, 18(S1): 281-284.
Apply the theory of fuzzy mathematics comprehensive evaluation of the integrated weighted points method to evaluate the site selection.
Apply the theory of fuzzy mathematics comprehensive evaluation of the integrated weighted points method to evaluate the site selection.
2010, 18(S1): 285-291.
The destruction of gas pipeline under surface load has been increasingly serious; therefore the safety evaluation of the stability of the gas pipeline under surface load becomes more and more important.In the paper,three dimensional numerical model of pipeline subject to load has been established,the deformation and mechanical state have been studied,and the influencing factors of mechanical state of pipeline have been classified.Consequently,the study has a practical significance to prevent and to research the pipeline disaster under surface load.
The destruction of gas pipeline under surface load has been increasingly serious; therefore the safety evaluation of the stability of the gas pipeline under surface load becomes more and more important.In the paper,three dimensional numerical model of pipeline subject to load has been established,the deformation and mechanical state have been studied,and the influencing factors of mechanical state of pipeline have been classified.Consequently,the study has a practical significance to prevent and to research the pipeline disaster under surface load.
2010, 18(S1): 292-296.
Soil-rock compound slope in the slope engineering is a typical slope type,its main feature is the interface between soil and rock often becomes a potential sliding surface of the slope,in this paper,on the background of anti-slide pile engineering of soil-rock compound slope,the calculation of landslide thrust by the traditional transfer coefficient method is improved,soil resistance before pile is calculated by elastic method,introducing the bi-parameter method,the internal force deflection differential equation of anti-slide pile is established,and the internal force and displacement calculation methods for different types anti-slide piles(rigid pile,elastic pile)are discussed,providing a new way to solve the internal force calculation problem of anti-slide pile of soil-rock compound slope effectively.Accordingly,an software which is object-oriented,formed a design,analysis,calculation and drawing computer-aided design system is prepared by VC method,improving the calculation speed and calculation accuracy significantly to achieving the optimal design for anti-slide piles,and the software is applied to the typical soil-rock compound slope engineering successfully,having reference value for similar engineering practice.
Soil-rock compound slope in the slope engineering is a typical slope type,its main feature is the interface between soil and rock often becomes a potential sliding surface of the slope,in this paper,on the background of anti-slide pile engineering of soil-rock compound slope,the calculation of landslide thrust by the traditional transfer coefficient method is improved,soil resistance before pile is calculated by elastic method,introducing the bi-parameter method,the internal force deflection differential equation of anti-slide pile is established,and the internal force and displacement calculation methods for different types anti-slide piles(rigid pile,elastic pile)are discussed,providing a new way to solve the internal force calculation problem of anti-slide pile of soil-rock compound slope effectively.Accordingly,an software which is object-oriented,formed a design,analysis,calculation and drawing computer-aided design system is prepared by VC method,improving the calculation speed and calculation accuracy significantly to achieving the optimal design for anti-slide piles,and the software is applied to the typical soil-rock compound slope engineering successfully,having reference value for similar engineering practice.
2010, 18(S1): 297-300.
The results of similarity model test show that,the laws of activated deformation is essentially different from the Laws of mining subsidence in goaf.As different mining methods,the development degree of residual fissure in different parts of the goaf has great difference,and the scope on Surface influented by residual fissure falling further and compaction is smaller than the one influented by mining subsidence.According to the results of similar simulation experiment and refered to the Previous treatment experience of highway goaf,we summarized reference value of overburden stratas displacement angle,proposed that determining the treatment depth according to the crack distribution of goaf and its laws of activated deformation.Compared to currently used methods,This method can greatly reduce the treatment scope and depth of goaf and save investment with significant economic benefits.Achievements will play an important role in promoting the use of treatment technology on goaf.
The results of similarity model test show that,the laws of activated deformation is essentially different from the Laws of mining subsidence in goaf.As different mining methods,the development degree of residual fissure in different parts of the goaf has great difference,and the scope on Surface influented by residual fissure falling further and compaction is smaller than the one influented by mining subsidence.According to the results of similar simulation experiment and refered to the Previous treatment experience of highway goaf,we summarized reference value of overburden stratas displacement angle,proposed that determining the treatment depth according to the crack distribution of goaf and its laws of activated deformation.Compared to currently used methods,This method can greatly reduce the treatment scope and depth of goaf and save investment with significant economic benefits.Achievements will play an important role in promoting the use of treatment technology on goaf.
2010, 18(S1): 301-305.
The core of urban planning engineering geology investigation is the evaluation of land construction suitability.In present code of urban planning investigation,it is employed single-factor nonnumeric evaluation method.Incorporating with the fuzziness and uncertainty of affecting factors for evaluation of land construction suitability,the fuzzy mathematics theory is applied after comprehensive analysis.the two-grade fuzzy evaluation model is taken via establishing evaluation index system which incorporates selection of main influential factors and determining the evaluation criterion for each impacting factor.The comprehensive fuzzy evaluation approach is primarily drawn on the determination of the membership idea and weight number for the factors.We use the expert evaluation method and the formula method in evaluating both the membership idea and weight number.The comprehensive fuzzy evaluation calculating process is illustrated with a case study.The afformentioned approach,which is applied into the evaluation for urban planning land construction suitability from the engineering geology and environmental geology perspectives,is a beneficial exploration.With the gradual deepening and advancing for urban planning engineering geology investigation,we strongly believe the specific approach will have had its applying prospect in the near future.
The core of urban planning engineering geology investigation is the evaluation of land construction suitability.In present code of urban planning investigation,it is employed single-factor nonnumeric evaluation method.Incorporating with the fuzziness and uncertainty of affecting factors for evaluation of land construction suitability,the fuzzy mathematics theory is applied after comprehensive analysis.the two-grade fuzzy evaluation model is taken via establishing evaluation index system which incorporates selection of main influential factors and determining the evaluation criterion for each impacting factor.The comprehensive fuzzy evaluation approach is primarily drawn on the determination of the membership idea and weight number for the factors.We use the expert evaluation method and the formula method in evaluating both the membership idea and weight number.The comprehensive fuzzy evaluation calculating process is illustrated with a case study.The afformentioned approach,which is applied into the evaluation for urban planning land construction suitability from the engineering geology and environmental geology perspectives,is a beneficial exploration.With the gradual deepening and advancing for urban planning engineering geology investigation,we strongly believe the specific approach will have had its applying prospect in the near future.
2010, 18(S1): 306-310.
Drainage consolidation is the best way to deal with large area of soft ground.But the effects of consolidation are adverse when the dredger fill is soft clay which initial moisture content is above 120%.In order to improve the efficiency and to optimize the progress of dredger fill consolidation,an orthogonal test was done.There were 4 test chambers installed in lab,including 2 kinds of drain pipes and 2 distances between drain pipes.Hyperbola model,exponential model and the amendments index model were used to predict the amount of the settlement.Comparison 4 kinds of tests,the largest surface settlement of dredger fill were found when using the domestic B-type drain pipe with spacing 40cm.And its settlement has the best modified exponential model.In this case the shortest time-consuming with 90% degree of consolidation was predicted for reference settlement.
Drainage consolidation is the best way to deal with large area of soft ground.But the effects of consolidation are adverse when the dredger fill is soft clay which initial moisture content is above 120%.In order to improve the efficiency and to optimize the progress of dredger fill consolidation,an orthogonal test was done.There were 4 test chambers installed in lab,including 2 kinds of drain pipes and 2 distances between drain pipes.Hyperbola model,exponential model and the amendments index model were used to predict the amount of the settlement.Comparison 4 kinds of tests,the largest surface settlement of dredger fill were found when using the domestic B-type drain pipe with spacing 40cm.And its settlement has the best modified exponential model.In this case the shortest time-consuming with 90% degree of consolidation was predicted for reference settlement.
2010, 18(S1): 311-314.
Pile-anchor retaining is preferred to be chosen in ultra-deep foundation pit or deep foundation pit that has bad condition.Among the methods in designing pile-anchor retaining system,Shanjianbangnan method is convenient by manual calculation that has little workload,and it can ensure the safety of the engineering as it considers the most dangerous force condition in each calculation step.The theory of the method is introduced first,then the foundation pit support design by the method is taken based on a project in LinYi city.The numerical simulation is taken to validate the feasibility of the design.It gives a reference to the same engineering.
Pile-anchor retaining is preferred to be chosen in ultra-deep foundation pit or deep foundation pit that has bad condition.Among the methods in designing pile-anchor retaining system,Shanjianbangnan method is convenient by manual calculation that has little workload,and it can ensure the safety of the engineering as it considers the most dangerous force condition in each calculation step.The theory of the method is introduced first,then the foundation pit support design by the method is taken based on a project in LinYi city.The numerical simulation is taken to validate the feasibility of the design.It gives a reference to the same engineering.
2010, 18(S1): 315-321.
Compare with slope collapse and landside,rockfall is only a kind of small scaled geological hazards.But it always occurs suddenly and hard to be forecasted,which can damage structures,transportation infrastructures and threaten human lives.Rockfalls happened widely in Wenchuan earthquake,which has brought about more attentions on this kind of hazards.Based on engineering practice,both the kinematics with probability and statistics and empirical formulae were used in calculating the velocity and kinetic energy of rockfall.Velocity and kinetic energy of rock blocks that may run along the high slopes are calculated when they arrive the location where a structure is planed to be built.The results of these two methods were analyzed.Only single values can be gained by empirical formulae while values in distribution can be calculated by the kinematics with probability and statistics for one slope.The result of velocity of the former method locates in the rage of bigger values in the results distribution of the latter method,which is in a rather safe rage.As the rotational kinetic energy is estimated smaller by empirical formulae than the kinematics with probability and statistics,the total kinetic energy is smaller accordingly by empirical formulae.By the above results and analyses,it is recommended to relocate the structure so as to prevent from being damaged in future rockfall that may happen.
Compare with slope collapse and landside,rockfall is only a kind of small scaled geological hazards.But it always occurs suddenly and hard to be forecasted,which can damage structures,transportation infrastructures and threaten human lives.Rockfalls happened widely in Wenchuan earthquake,which has brought about more attentions on this kind of hazards.Based on engineering practice,both the kinematics with probability and statistics and empirical formulae were used in calculating the velocity and kinetic energy of rockfall.Velocity and kinetic energy of rock blocks that may run along the high slopes are calculated when they arrive the location where a structure is planed to be built.The results of these two methods were analyzed.Only single values can be gained by empirical formulae while values in distribution can be calculated by the kinematics with probability and statistics for one slope.The result of velocity of the former method locates in the rage of bigger values in the results distribution of the latter method,which is in a rather safe rage.As the rotational kinetic energy is estimated smaller by empirical formulae than the kinematics with probability and statistics,the total kinetic energy is smaller accordingly by empirical formulae.By the above results and analyses,it is recommended to relocate the structure so as to prevent from being damaged in future rockfall that may happen.
2010, 18(S1): 322-326.
This paper presents an expereimental study to contrast the mechanical behaviors of the urea-formaldehyde resin and cement grouted fractured rocks.The urea-formaldehyde resin grout shows better liquidity,permeability and cohensive property,therefore,the urea-formaldehyde resin grouted fractured rocks perform more stably,and stronger than cement grouts.The experiment also show that mechanical behaviors will be more greatly improved,if the fractured rocks mechanical behaviors are relatively low.
This paper presents an expereimental study to contrast the mechanical behaviors of the urea-formaldehyde resin and cement grouted fractured rocks.The urea-formaldehyde resin grout shows better liquidity,permeability and cohensive property,therefore,the urea-formaldehyde resin grouted fractured rocks perform more stably,and stronger than cement grouts.The experiment also show that mechanical behaviors will be more greatly improved,if the fractured rocks mechanical behaviors are relatively low.
2010, 18(S1): 327-330.
Based on hydrogeological principle,the water level reduction method was adopted combined with water balance calculation to evaluate the groundwater resources in Qitai town,Shangdu county.Conditions of groundwater recharge,runoff and drainage were found out basically.The thickness and distribution area,water abundance and groundwater quality and variation of the phreatic aquifer of Tertiary(Pliocene)and Quaternary were ascertained.Distribution,water abundance character and water rich section of aquifer in Eocene of Tertiary were also determined.And the result of evaluation shows that the design production volume 367.99?104m3 穉-1 of this watershed can be guaranteed,which can provide reference to exploitation and utility of water resource in Qitai town,Shangdu county.
Based on hydrogeological principle,the water level reduction method was adopted combined with water balance calculation to evaluate the groundwater resources in Qitai town,Shangdu county.Conditions of groundwater recharge,runoff and drainage were found out basically.The thickness and distribution area,water abundance and groundwater quality and variation of the phreatic aquifer of Tertiary(Pliocene)and Quaternary were ascertained.Distribution,water abundance character and water rich section of aquifer in Eocene of Tertiary were also determined.And the result of evaluation shows that the design production volume 367.99?104m3 穉-1 of this watershed can be guaranteed,which can provide reference to exploitation and utility of water resource in Qitai town,Shangdu county.
2010, 18(S1): 331-334.
Post grouting technology for bored pile has been widely used in many areas in China.After the descriptions of the principle of post grouting technology and the construction technical requirements,the applications of post grounting technology in Xi'an under different geological conditions,building type and foundation treatment were mainly introduced by engineering examples,then the experimental detection and the reliability evaluation on application effects were presented.
Post grouting technology for bored pile has been widely used in many areas in China.After the descriptions of the principle of post grouting technology and the construction technical requirements,the applications of post grounting technology in Xi'an under different geological conditions,building type and foundation treatment were mainly introduced by engineering examples,then the experimental detection and the reliability evaluation on application effects were presented.
2010, 18(S1): 335-339.
This paper studied the outcropped and engineering properties of granite residual soil in Haicang region of Xiamen province through cone penetration test and standard penetration test methods.The concept of "horizon depth" was put forward and it was concluded that the horizon depth and the in-situ test data had a linear dependence relation.The cone penetration test was employed to study the bearing capacity characteristic value and deformation modulus of granite residual soil,and relationship between the specific penetration resistance and the deformation modulus was defined,they are also with a linear dependence relation.The results of pilot calculation and in-situ test are anastomotic basically,which proved that granite residual soil has obvious characters in vertical direction.
This paper studied the outcropped and engineering properties of granite residual soil in Haicang region of Xiamen province through cone penetration test and standard penetration test methods.The concept of "horizon depth" was put forward and it was concluded that the horizon depth and the in-situ test data had a linear dependence relation.The cone penetration test was employed to study the bearing capacity characteristic value and deformation modulus of granite residual soil,and relationship between the specific penetration resistance and the deformation modulus was defined,they are also with a linear dependence relation.The results of pilot calculation and in-situ test are anastomotic basically,which proved that granite residual soil has obvious characters in vertical direction.
2010, 18(S1): 340-345.
Geological hazards occurs frequently along the gas transmission pipeline project between Zhongxian city and Wuhan city,especially the medium to small size landslide due to be discovered difficultly or not be emphasized. The safety of the gas pipeline is seriously threatened by the landslides. Therefore,it is necessary to research the damage of the gas transmission pipeline caused by the landslides. Xiaodanziya landslide along the gas transportation pipeline between Zhongxian city and Wuhan city taken as an example,the paper discusses the common position and the mechanism relation between landslide and pipeline,establishes the mechanical model and discusses the factors of affecting the mechanical characters of pipeline. The research results are shown as follow: (1)the both ends and center of the pipeline is easy to be damaged by the sliding force of landslide,especially the both ends; (2)small landslide force q can cause the disadvantage state of stress of the gas pipeline. Therefore,the protection of the gas transmission pipeline needs to be paid more attention; (3)With the effect of Landslide,axial force on pipeline transform between tensile stress and compressive stress due to a change of pipeline to internal pressure and the result of operating temperature minus laying temperature.
Geological hazards occurs frequently along the gas transmission pipeline project between Zhongxian city and Wuhan city,especially the medium to small size landslide due to be discovered difficultly or not be emphasized. The safety of the gas pipeline is seriously threatened by the landslides. Therefore,it is necessary to research the damage of the gas transmission pipeline caused by the landslides. Xiaodanziya landslide along the gas transportation pipeline between Zhongxian city and Wuhan city taken as an example,the paper discusses the common position and the mechanism relation between landslide and pipeline,establishes the mechanical model and discusses the factors of affecting the mechanical characters of pipeline. The research results are shown as follow: (1)the both ends and center of the pipeline is easy to be damaged by the sliding force of landslide,especially the both ends; (2)small landslide force q can cause the disadvantage state of stress of the gas pipeline. Therefore,the protection of the gas transmission pipeline needs to be paid more attention; (3)With the effect of Landslide,axial force on pipeline transform between tensile stress and compressive stress due to a change of pipeline to internal pressure and the result of operating temperature minus laying temperature.
2010, 18(S1): 346-352.
JingDu landslide group,which consists of landslide HP1and landslide HP2,occurred in the hilly areas of low mountain front.The rhyolitic tuff and its weathered material are revealed mainly around the landslide field.Landslide HP1,as an existing landslide,slid again.At the same time,landslide HP2 was triggered by HP1.It is found that the sliding body is mostly composed of gravel soil and silty clay mixed with mass rock,the soil of sliding zone is mostly composed of plastic brown-yellow and brown-red cohesive clay,and the sliding bed is composed of completely decomposed thyolitic tuff.The property and mechanism of formation are also demonstrated for the JingDu landslide group through analyzing the characteristic of deformation and the engineering geology condition.Moreover,the effect of rainfall upon landslide is discussed.It is concluded that the excavation at the foot of the slope,which resulted in the failure of the brace on the foot of the slope,resulted in the development of the landslide group.The continuous and excessive rainfall is only the inducing factors.The occurrence of the deep-seated slide doesnt correlate necessarily with rainfall.However the continuous rainfall can reduce the dynamic stability of the deep-seated landslide and promotes the occurring of sliding.The weathered tuff,which distributed widely in Shenzhen area,can develop into sliding-prone stratum under the suitable hydrogeology condition.
JingDu landslide group,which consists of landslide HP1and landslide HP2,occurred in the hilly areas of low mountain front.The rhyolitic tuff and its weathered material are revealed mainly around the landslide field.Landslide HP1,as an existing landslide,slid again.At the same time,landslide HP2 was triggered by HP1.It is found that the sliding body is mostly composed of gravel soil and silty clay mixed with mass rock,the soil of sliding zone is mostly composed of plastic brown-yellow and brown-red cohesive clay,and the sliding bed is composed of completely decomposed thyolitic tuff.The property and mechanism of formation are also demonstrated for the JingDu landslide group through analyzing the characteristic of deformation and the engineering geology condition.Moreover,the effect of rainfall upon landslide is discussed.It is concluded that the excavation at the foot of the slope,which resulted in the failure of the brace on the foot of the slope,resulted in the development of the landslide group.The continuous and excessive rainfall is only the inducing factors.The occurrence of the deep-seated slide doesnt correlate necessarily with rainfall.However the continuous rainfall can reduce the dynamic stability of the deep-seated landslide and promotes the occurring of sliding.The weathered tuff,which distributed widely in Shenzhen area,can develop into sliding-prone stratum under the suitable hydrogeology condition.
2010, 18(S1): 353-365.
Wenchuan Earthquake of Ms8.0 showed that the most severe geological hazards occurred in the meisoseismal area,demonstrated by higher density,larger scales and greater distribution of rock slides than those adjacent areas.Therefore,characteristics of seismic waves,geological structures of rock masses,and mechanical strength over the plane of weakness should be considered in stability assessment of rock slopes and prediction of rock slides in a meisoseismal area.The author assessed existing methods and concluded that these methods may not produce realistic predictions because they only took into account of effects of the horizontal acceleration of seismic waves.Based on structural mechanics of rock masses and analysis of rock strength,the author hypothesized that the slides in a meisoseismal area can be caused by tensile,shear failures,or a combination of them along a plane of weakness.In consideration of a large angle of incidence hitting land surface in a meisoseismal area,one should apply combined effects of seismic force vectors in assessment of slope stability as well as effects of P and S waves.In this paper,two common types of simple geological models were used,namely a single plane of weakness and dual planes of weakness.Five types of failure patterns were defined under the specified critical failure acceleration based on limited equilibrium principles.The critical failure acceleration can be obtained by inputting the angle of incidence of the earthquake wave,geometry for the plane of weakness and its mechanical properties.It can then be compared with the directional acceleration rate converted from the real earthquake acceleration vector to determine failure types for generation of sliding planes and assessment of slope stability.It should be emphasized that detail engineering geological investigation is fundamental for this presented method to achieve better results.
Wenchuan Earthquake of Ms8.0 showed that the most severe geological hazards occurred in the meisoseismal area,demonstrated by higher density,larger scales and greater distribution of rock slides than those adjacent areas.Therefore,characteristics of seismic waves,geological structures of rock masses,and mechanical strength over the plane of weakness should be considered in stability assessment of rock slopes and prediction of rock slides in a meisoseismal area.The author assessed existing methods and concluded that these methods may not produce realistic predictions because they only took into account of effects of the horizontal acceleration of seismic waves.Based on structural mechanics of rock masses and analysis of rock strength,the author hypothesized that the slides in a meisoseismal area can be caused by tensile,shear failures,or a combination of them along a plane of weakness.In consideration of a large angle of incidence hitting land surface in a meisoseismal area,one should apply combined effects of seismic force vectors in assessment of slope stability as well as effects of P and S waves.In this paper,two common types of simple geological models were used,namely a single plane of weakness and dual planes of weakness.Five types of failure patterns were defined under the specified critical failure acceleration based on limited equilibrium principles.The critical failure acceleration can be obtained by inputting the angle of incidence of the earthquake wave,geometry for the plane of weakness and its mechanical properties.It can then be compared with the directional acceleration rate converted from the real earthquake acceleration vector to determine failure types for generation of sliding planes and assessment of slope stability.It should be emphasized that detail engineering geological investigation is fundamental for this presented method to achieve better results.
2010, 18(S1): 366-368.
An assessment method of landslides in village and small town was proposed in this paper. Based on the probability and grades of landslide hazard,the landslide risk was divided into small,medium,and large grades. Based on the landslide risk and the capacity to cure landslide,the site of village and small town was divided into four categories: no fit,poor fit,fair fit,and fit. A simple supervision method to landslides was also proposed. The supervision method included simple displacement supervision and macro phenomena of critical state of landslides. Consequently,an effective method to prevent and cure landslides in village and small town was discussed.
An assessment method of landslides in village and small town was proposed in this paper. Based on the probability and grades of landslide hazard,the landslide risk was divided into small,medium,and large grades. Based on the landslide risk and the capacity to cure landslide,the site of village and small town was divided into four categories: no fit,poor fit,fair fit,and fit. A simple supervision method to landslides was also proposed. The supervision method included simple displacement supervision and macro phenomena of critical state of landslides. Consequently,an effective method to prevent and cure landslides in village and small town was discussed.
2010, 18(S1): 369-373.
There are many dykes intersecting in the spillway entrance section and the slope,so the geological conditions are poor,the roof fall occurred because of not timely supporting when excavated,but before the roof falled,and more displacement meter and other monitoring equipment monitored the varying degrees of mutation,geological forecasts also timely predicted the type of surrounding rock and safety prediction according to the excavation condition,this played a forecasting and remindering role in instructing construction and personnel safety.
There are many dykes intersecting in the spillway entrance section and the slope,so the geological conditions are poor,the roof fall occurred because of not timely supporting when excavated,but before the roof falled,and more displacement meter and other monitoring equipment monitored the varying degrees of mutation,geological forecasts also timely predicted the type of surrounding rock and safety prediction according to the excavation condition,this played a forecasting and remindering role in instructing construction and personnel safety.
2010, 18(S1): 374-383.
The study on the landslide moving and river-blocking mechanism is the starting point of the studies of the landslide river-blocking disaster chain.Many landslides,avalanches and other geological hazards occurred during the "5.12" Wenchuan earthquake, 2008.And most of these hazards happened in the high mountain gorge areas.The moving distance of the landslide was very short,and has the characteristics of "high speed and short route","river-blocking" and so on.Taking Tangjiashan landslide which is the most dangerous river-blocking hazards happened during the earthquake as an example,the 3D instability process of the landslide is reconstructed by using dynamic finite element method based on detailed geologic investigation results of the landslide area.With the analytical results,the forming process and river-blocking mechanism of Tangjiashan landslide can be divided into four phases:(1)earthquake triggering and progressive failure of the rock mass; (2)landslide body failure and sliding in high speed; (3)impacting the opposite slope,disintegrated,blocking the river and the landslide dam formed; (4)density under the impacting.At about 30s after the earthquake the average velocity of Tangjiashan landslide body reaches its maximum value,about 22m 穝-1; and at about 65s,the movement of the landslide reaches to the stabile statues.
The study on the landslide moving and river-blocking mechanism is the starting point of the studies of the landslide river-blocking disaster chain.Many landslides,avalanches and other geological hazards occurred during the "5.12" Wenchuan earthquake, 2008.And most of these hazards happened in the high mountain gorge areas.The moving distance of the landslide was very short,and has the characteristics of "high speed and short route","river-blocking" and so on.Taking Tangjiashan landslide which is the most dangerous river-blocking hazards happened during the earthquake as an example,the 3D instability process of the landslide is reconstructed by using dynamic finite element method based on detailed geologic investigation results of the landslide area.With the analytical results,the forming process and river-blocking mechanism of Tangjiashan landslide can be divided into four phases:(1)earthquake triggering and progressive failure of the rock mass; (2)landslide body failure and sliding in high speed; (3)impacting the opposite slope,disintegrated,blocking the river and the landslide dam formed; (4)density under the impacting.At about 30s after the earthquake the average velocity of Tangjiashan landslide body reaches its maximum value,about 22m 穝-1; and at about 65s,the movement of the landslide reaches to the stabile statues.
ANALYSIS ON REVIVAL MECHANISM OF AN ANCIENT LANDSLIDE AT SECTION K48+125～230 OF JINPING SPECIAL ROAD
2010, 18(S1): 384-390.
An ancient accumulation landslide is located at the section K48+125～K48+230 of Jinping special road.During the rainy season in 2008(after the road is completed),a series of strong deformations occurred in the middle-lower of the landslide.According to analysis on revival deformation phenomena,geological and environmental conditions of the study area,it is derived that the revival deformation is mainly caused from cutting partly at the toe of the landslide.Heavy rainfall in 2008 has new slide-plane to be run-through and the middle-lower of the landslide to slide as a whole.The spoon-shaped slide-plane is a main internal factor controlling the development of deformation.The development process of new slide-surface is simulated by FLAC2D.After both the filling back and the sheet piled wall with anchor ropes are carried out,the sliding-mass stability factor will increase from 0.977 to 1.183 under rainfall conditions(design conditions)by Transmission Coefficient Method,which meet the safety requirements.It is shown by in-situ inspection that the landslide has no any new revival deformation phenomena to occur,which verifies the analysis on the genetic mechanism in this paper.
An ancient accumulation landslide is located at the section K48+125～K48+230 of Jinping special road.During the rainy season in 2008(after the road is completed),a series of strong deformations occurred in the middle-lower of the landslide.According to analysis on revival deformation phenomena,geological and environmental conditions of the study area,it is derived that the revival deformation is mainly caused from cutting partly at the toe of the landslide.Heavy rainfall in 2008 has new slide-plane to be run-through and the middle-lower of the landslide to slide as a whole.The spoon-shaped slide-plane is a main internal factor controlling the development of deformation.The development process of new slide-surface is simulated by FLAC2D.After both the filling back and the sheet piled wall with anchor ropes are carried out,the sliding-mass stability factor will increase from 0.977 to 1.183 under rainfall conditions(design conditions)by Transmission Coefficient Method,which meet the safety requirements.It is shown by in-situ inspection that the landslide has no any new revival deformation phenomena to occur,which verifies the analysis on the genetic mechanism in this paper.
2010, 18(S1): 391-395.
In order to solve the problem of accumulative landslide instability under rainfall,this paper presents a simple mechanical model considering the fissure water in trailing edge fracture of landslide. The landside system being at a quasi-static state in balance curved surface,the systems total potential energy function is established. So the dynamic instability cusp catastrophe model of the landslide system is generalized. When passing through the curve of fold bifurcations,the common equations of shear displacement jump、energy release and the slip bands velocity are obtained. The material constitutive relationship of Weibull distribution is introduced into the generalized fold model as a example. Through the fold bifurcation analysis of the cusp catastrophe,it is got that the landslide dynamic instability is the combined effect of internal and external results under rainfall. And this deepens the understanding of the mechanism of landslide instability.
In order to solve the problem of accumulative landslide instability under rainfall,this paper presents a simple mechanical model considering the fissure water in trailing edge fracture of landslide. The landside system being at a quasi-static state in balance curved surface,the systems total potential energy function is established. So the dynamic instability cusp catastrophe model of the landslide system is generalized. When passing through the curve of fold bifurcations,the common equations of shear displacement jump、energy release and the slip bands velocity are obtained. The material constitutive relationship of Weibull distribution is introduced into the generalized fold model as a example. Through the fold bifurcation analysis of the cusp catastrophe,it is got that the landslide dynamic instability is the combined effect of internal and external results under rainfall. And this deepens the understanding of the mechanism of landslide instability.
2010, 18(S1): 396-405.
Geo-hazards that triggered by the Wenchuan Ms8.0 earthquake along the Dujiangyan to Wenchuan Highway are especially severe and have seriously affected the safe riding along the highway and the reconstructions.In order to prevent and reduce disasters effectively,regional geological hazards have been studied in the area on the basis of the field investigations and statistic analysis of available data.The results show the following three prominent characteristics of hazards in the area: in terms of distribution geologic hazards are linear ribbon and intensively,have many types and are notably divided into sectors; the high and steep rock deposits of complex origin form the main material foundation of geological hazards; intense earthquake effect and coupling of androgenic and exogamic forces are the important factors for the formation and occurrence of geological hazards in the area.This paper provides a scientific basis for the study of the mechanism of occurrence of the geo-hazards triggered by earthquake in the area and measures for their prevention and control.
Geo-hazards that triggered by the Wenchuan Ms8.0 earthquake along the Dujiangyan to Wenchuan Highway are especially severe and have seriously affected the safe riding along the highway and the reconstructions.In order to prevent and reduce disasters effectively,regional geological hazards have been studied in the area on the basis of the field investigations and statistic analysis of available data.The results show the following three prominent characteristics of hazards in the area: in terms of distribution geologic hazards are linear ribbon and intensively,have many types and are notably divided into sectors; the high and steep rock deposits of complex origin form the main material foundation of geological hazards; intense earthquake effect and coupling of androgenic and exogamic forces are the important factors for the formation and occurrence of geological hazards in the area.This paper provides a scientific basis for the study of the mechanism of occurrence of the geo-hazards triggered by earthquake in the area and measures for their prevention and control.
2010, 18(S1): 406-412.
Floods and landslides account for the two major geo-hazards. A Global Hazard System(GHS)is introduced together with some application in early warning the two geo-hazards.Based on integrating remote sensing tools in prediction of floods and landslides,a prototype GHS that incorporates satellite-based near real-time rainfall flux into a hydrological model and landslide model is developed by NASA TRMM research group.Case studies in Honduras,Indonesia,and China show the prediction ability of GHS in regional scale,and results show that landslides could be predicted temporally and spatially.Extending application in Fujian Province also will be implemented in the future.
Floods and landslides account for the two major geo-hazards. A Global Hazard System(GHS)is introduced together with some application in early warning the two geo-hazards.Based on integrating remote sensing tools in prediction of floods and landslides,a prototype GHS that incorporates satellite-based near real-time rainfall flux into a hydrological model and landslide model is developed by NASA TRMM research group.Case studies in Honduras,Indonesia,and China show the prediction ability of GHS in regional scale,and results show that landslides could be predicted temporally and spatially.Extending application in Fujian Province also will be implemented in the future.
2010, 18(S1): 413-416.
This paper analyzed the landform,topographical features,formation and geological structure of Haibo bay district in Wuhai city,based on geohazard theory and analysis on the incurred geohazards,this paper demonstrated that the main type of geohazards in this area were collapse and ground collapse.Collapse is mainly distributed at low relief terrain,and ground collapse is mainly distributed at hilly area and worked-out section of coal mine.The main type of ground collapse is roof fall.
This paper analyzed the landform,topographical features,formation and geological structure of Haibo bay district in Wuhai city,based on geohazard theory and analysis on the incurred geohazards,this paper demonstrated that the main type of geohazards in this area were collapse and ground collapse.Collapse is mainly distributed at low relief terrain,and ground collapse is mainly distributed at hilly area and worked-out section of coal mine.The main type of ground collapse is roof fall.
2010, 18(S1): 417-421.
A survey found that geological environment problems perplex urban development caused by human activities account for more than 70% of all problems.Prevention of urban geological hazards is needed to transfer from passive reaction to active protection urgently.According to different type of land utilization,different risk assessment of geological hazards is carried out and the risk level of geological hazards under certain land use type is obtained,simultaneously geological hazards risk regionalization for land use is carried out and the division is put into land use planning for land use zoning and control of geological hazards risk.Take Pan Zhi-hua for example,risk assessment and zoning of geological hazards such as collapse,landslide,debris and land collapse,urban geological hazards risk map is compounded with urban land use planning map to make "Geological hazards risk control & proposal map for urban land use planning",then the map is brought into urban land use planning regulation and a new method is provided for urban geological hazards risk prevention.
A survey found that geological environment problems perplex urban development caused by human activities account for more than 70% of all problems.Prevention of urban geological hazards is needed to transfer from passive reaction to active protection urgently.According to different type of land utilization,different risk assessment of geological hazards is carried out and the risk level of geological hazards under certain land use type is obtained,simultaneously geological hazards risk regionalization for land use is carried out and the division is put into land use planning for land use zoning and control of geological hazards risk.Take Pan Zhi-hua for example,risk assessment and zoning of geological hazards such as collapse,landslide,debris and land collapse,urban geological hazards risk map is compounded with urban land use planning map to make "Geological hazards risk control & proposal map for urban land use planning",then the map is brought into urban land use planning regulation and a new method is provided for urban geological hazards risk prevention.
2010, 18(S1): 422-427.
Small towns are the link connecting major cities and villages,their rapidly development is significantly restricted by geological disasters.Geological hazard assessment is objective need for sustainable development of small towns.Taking Longshan town and Agan town as examples,we have established three-level fuzzy comprehensive evaluation model of geological hazard assessment and detailed evaluation index system,identified the main geological disaster types are landslide,debris flow,unstable slope and land collapse et al,carried out three-level fuzzy comprehensive evaluation of geological hazard.The results show that: in accordance with the four level of not easy-happening,low easy-happening,medium easy-happening and high easy-happening,Longshan town is low easy-happening area and Agan town is high easy-happening area of geological hazards,the results are more close to the reality.It shows that multi-level fuzzy comprehensive method is an effective way to achieve the transition from single-factor qualitative evaluation to multi-factor quantitative comprehensive evaluation in the evaluation of geological hazard.
Small towns are the link connecting major cities and villages,their rapidly development is significantly restricted by geological disasters.Geological hazard assessment is objective need for sustainable development of small towns.Taking Longshan town and Agan town as examples,we have established three-level fuzzy comprehensive evaluation model of geological hazard assessment and detailed evaluation index system,identified the main geological disaster types are landslide,debris flow,unstable slope and land collapse et al,carried out three-level fuzzy comprehensive evaluation of geological hazard.The results show that: in accordance with the four level of not easy-happening,low easy-happening,medium easy-happening and high easy-happening,Longshan town is low easy-happening area and Agan town is high easy-happening area of geological hazards,the results are more close to the reality.It shows that multi-level fuzzy comprehensive method is an effective way to achieve the transition from single-factor qualitative evaluation to multi-factor quantitative comprehensive evaluation in the evaluation of geological hazard.
2010, 18(S1): 428-433.
Karst is a process and result of groundwater geologic function and is one of bad geological phenomenon facing tunnel construction.It is important for construction of tunnel to study the distribution and growing rules of karst area. The lithology and the hydrological conditions had been investigated by means of drilling and physical exploration.Based on the analysis of the geological structure,cover property,namely distribution,sizes and filling of karst,the extent and rule of karst development were clarified.It sums up the karst ecological environment of XangJang tunnel,analyses the construction adventure of karst to track,and put forward the corresponding keeping away steps,and this supplies reference to the specific project of this section.
Karst is a process and result of groundwater geologic function and is one of bad geological phenomenon facing tunnel construction.It is important for construction of tunnel to study the distribution and growing rules of karst area. The lithology and the hydrological conditions had been investigated by means of drilling and physical exploration.Based on the analysis of the geological structure,cover property,namely distribution,sizes and filling of karst,the extent and rule of karst development were clarified.It sums up the karst ecological environment of XangJang tunnel,analyses the construction adventure of karst to track,and put forward the corresponding keeping away steps,and this supplies reference to the specific project of this section.
2010, 18(S1): 434-438.
Longkou coal mining area is one of the few mining areas around the east sea line,which is focus on E coal measures.It is indicated by production practice that the main coal seam of Longkou coal mining area contains a low content of gas,but the excavated spaces always contain high content of gas in various coal mines.In this paper,based on analysis of the geological structures and gas geological characteristics,the existing laws of coal gas and their control factors have been summarized systematically,and the distribution of coal gas in different coal mines and their hazard have been assessed,which have important instruction for security production for coal mines.
Longkou coal mining area is one of the few mining areas around the east sea line,which is focus on E coal measures.It is indicated by production practice that the main coal seam of Longkou coal mining area contains a low content of gas,but the excavated spaces always contain high content of gas in various coal mines.In this paper,based on analysis of the geological structures and gas geological characteristics,the existing laws of coal gas and their control factors have been summarized systematically,and the distribution of coal gas in different coal mines and their hazard have been assessed,which have important instruction for security production for coal mines.
2010, 18(S1): 439-444.
Based on a comprehensive review of current status of risk assessment in the rocky desertification areas and considering the causes of rocky desertification,a new hazard degree assessment index system for rocky desertification areas was proposed in this paper.Afterwards,index weight has been quantified and normalized.And finally,with the vulnerable degree for assessment of debris flow,the vulnerable degree and the risk index for the assessment of rocky desertification have been obtained.
Based on a comprehensive review of current status of risk assessment in the rocky desertification areas and considering the causes of rocky desertification,a new hazard degree assessment index system for rocky desertification areas was proposed in this paper.Afterwards,index weight has been quantified and normalized.And finally,with the vulnerable degree for assessment of debris flow,the vulnerable degree and the risk index for the assessment of rocky desertification have been obtained.
2010, 18(S1): 445-449.
We can generally see pretty rockfall at the scenic spot of mountain region of our country. In this text,the author define it as the landscape of Perilous Rock,which having the value of the visual,infectious,unique,magic value of tourism and aesthetic appreciation. These special rockfall is the Geological heritage obviously,as it is scarce,precious,fragility and non-renewable. At present,the overall level of theoretical studies of rockfall is non-high,landscape of Perilous Rock stilling in its infancy. However,in tourism developing and protecting the geological heritage of scenic spot of mountain region,we have met a lot problem of landscape-rockfall,so it is more prominent that studying landscape-rockfall is more and more urgent and important. Depth studying unstable rock landscape features makes the wonderful and elegant grand rockfall to play tour value and lessen its danger,this according with the strategy of sustainable development of every scenic spot and producing the enormous social effect in the future. Under these backgrounds,this text has set up the research frame of landscape-rockfall and gives some difficult problem to be solved urgently at present. The content of researching landscape-rockfall includes its survey,formation mechanism,risk assessment and prevention countermeasure. Meanwhile,this text put forward five principles to landscape-rockfall disaster prevention,nondestructibility,approximability,reversibility,no interference and compatibility.
We can generally see pretty rockfall at the scenic spot of mountain region of our country. In this text,the author define it as the landscape of Perilous Rock,which having the value of the visual,infectious,unique,magic value of tourism and aesthetic appreciation. These special rockfall is the Geological heritage obviously,as it is scarce,precious,fragility and non-renewable. At present,the overall level of theoretical studies of rockfall is non-high,landscape of Perilous Rock stilling in its infancy. However,in tourism developing and protecting the geological heritage of scenic spot of mountain region,we have met a lot problem of landscape-rockfall,so it is more prominent that studying landscape-rockfall is more and more urgent and important. Depth studying unstable rock landscape features makes the wonderful and elegant grand rockfall to play tour value and lessen its danger,this according with the strategy of sustainable development of every scenic spot and producing the enormous social effect in the future. Under these backgrounds,this text has set up the research frame of landscape-rockfall and gives some difficult problem to be solved urgently at present. The content of researching landscape-rockfall includes its survey,formation mechanism,risk assessment and prevention countermeasure. Meanwhile,this text put forward five principles to landscape-rockfall disaster prevention,nondestructibility,approximability,reversibility,no interference and compatibility.
2010, 18(S1): 450-454.
The distribution feature of grotto and stature on cliff in Sichuan,China,stratum and lithological characters where grotto and stature on cliff located were introducted first in this paper.Main problems of grotto and stature on cliff in Sichuan,China,such as weathering decorticate,vadose water and weed infestation on the surface of grotto and stature on cliff,instability of and rock-mass where grotto and stature on cliff located and both sides of grotto and stature on cliff due to the decompression crack behind the grotto and stature on cliff were summed up,and countermeasure for main problems were researched.
The distribution feature of grotto and stature on cliff in Sichuan,China,stratum and lithological characters where grotto and stature on cliff located were introducted first in this paper.Main problems of grotto and stature on cliff in Sichuan,China,such as weathering decorticate,vadose water and weed infestation on the surface of grotto and stature on cliff,instability of and rock-mass where grotto and stature on cliff located and both sides of grotto and stature on cliff due to the decompression crack behind the grotto and stature on cliff were summed up,and countermeasure for main problems were researched.
2010, 18(S1): 455-462.
As one of the four most famous historical hydrological engineering projects,theTuoshan Weir,sitting at Ningjiang Town,Ningbo City,is well preserved with normal operation up to now.From its construction at 833 AD,Tang Dynasty,it plays roles in isolation of salty(sea)water,prevention of flooding and irrigation in this area.From viewpoints of scientific plan,design and construction,this paper presents the high level of wisdom recorded in this hydrological engineering from 8aspects as hydraulics,mechanics,etc.
As one of the four most famous historical hydrological engineering projects,theTuoshan Weir,sitting at Ningjiang Town,Ningbo City,is well preserved with normal operation up to now.From its construction at 833 AD,Tang Dynasty,it plays roles in isolation of salty(sea)water,prevention of flooding and irrigation in this area.From viewpoints of scientific plan,design and construction,this paper presents the high level of wisdom recorded in this hydrological engineering from 8aspects as hydraulics,mechanics,etc.
2010, 18(S1): 463-467.
Five shrubs planted for five years in the testing areas were studied.They are Caragana korshinskii,Zygophyllum xanthoxylon,Nitraria tangutorum,Atriplex canescens and Lycium chinense.Through the observation of the up-ground growing increment and the statistics results of the five shrubs,the factors influencing the hydrological effects for slope protection were explored.The results show: the up-ground growing increment of shrubs have an effect on their hydrological effects and the slope protection; plant height and diameter have different effects on the shrubs hydrological effects,and although the shrubs have the same growing period,their influences about their up-ground growing increment on the effects of both hydrological and slope protection are quite different.The study helps to choose the kind of shrubs which have better effects in the hydrological effect and slope protection.
Five shrubs planted for five years in the testing areas were studied.They are Caragana korshinskii,Zygophyllum xanthoxylon,Nitraria tangutorum,Atriplex canescens and Lycium chinense.Through the observation of the up-ground growing increment and the statistics results of the five shrubs,the factors influencing the hydrological effects for slope protection were explored.The results show: the up-ground growing increment of shrubs have an effect on their hydrological effects and the slope protection; plant height and diameter have different effects on the shrubs hydrological effects,and although the shrubs have the same growing period,their influences about their up-ground growing increment on the effects of both hydrological and slope protection are quite different.The study helps to choose the kind of shrubs which have better effects in the hydrological effect and slope protection.
2010, 18(S1): 468-474.
Earthquake is an important factor in triggering landslides,the Wenchuan earthquake caused many landslides hazards in Longmenshan region.Affected by strong earthquake,many deposits which are stable in natural conditions become unstable.On the basis of geological investigation to deposits landslide in the region,clarify the deformation mechanism of the landslide by the effect of earthquake.Adopted finite element simulated its stability state under earthquake,analysis the dynamic response feature under earthquake.Also we studied the features of instable probability of accumulation deposits landslide under earthquake.It is comprehensive that the landslide is less stable in the earthquake effect and thus evaluated the stability of the landslide reasonable.
Earthquake is an important factor in triggering landslides,the Wenchuan earthquake caused many landslides hazards in Longmenshan region.Affected by strong earthquake,many deposits which are stable in natural conditions become unstable.On the basis of geological investigation to deposits landslide in the region,clarify the deformation mechanism of the landslide by the effect of earthquake.Adopted finite element simulated its stability state under earthquake,analysis the dynamic response feature under earthquake.Also we studied the features of instable probability of accumulation deposits landslide under earthquake.It is comprehensive that the landslide is less stable in the earthquake effect and thus evaluated the stability of the landslide reasonable.
2010, 18(S1): 475-481.
Collapsing and sliding responses of Lengjin valley steep bedding rock slope landslide is triggered by"5.12"Wenchuan earthquake,in Chaping town,An xian country.The key controlling factor of collapsing and sliding of the slope is long duration of strong earthquake force.It had special destruction features in its dynamic processes,the failure mechanism is mainly contained collapsing and sliding.This text use two-dimensional discrete element numerical simulation and analyse the acceleration response rules by the slope internal monitoring data,some conclusions are obtained as following:as the elevation increases,the dynamic response acceleration shows increasing in the trend of nonlinear; as the distance from slope surface decreasing,the dynamic response acceleration increased and the peak acceleration of slope surface was significantly increased; the peak effect of dynamic response acceleration occurred around the crest of the slope.Based on the acceleration dynamic response analysis,the slope collapsing and sliding failure mechanism is analysed.The result show that: first,the slope shattering-cracking and relaxed induced by strong earthquake,joint fissures opened and run through; with the shock effect of the seismic forces periodically,the rock-mass fragmentated and disintegrated in the lower part; the high mass has lost support,and the slope overall shattering-slided by the bedding plane eventually.
Collapsing and sliding responses of Lengjin valley steep bedding rock slope landslide is triggered by"5.12"Wenchuan earthquake,in Chaping town,An xian country.The key controlling factor of collapsing and sliding of the slope is long duration of strong earthquake force.It had special destruction features in its dynamic processes,the failure mechanism is mainly contained collapsing and sliding.This text use two-dimensional discrete element numerical simulation and analyse the acceleration response rules by the slope internal monitoring data,some conclusions are obtained as following:as the elevation increases,the dynamic response acceleration shows increasing in the trend of nonlinear; as the distance from slope surface decreasing,the dynamic response acceleration increased and the peak acceleration of slope surface was significantly increased; the peak effect of dynamic response acceleration occurred around the crest of the slope.Based on the acceleration dynamic response analysis,the slope collapsing and sliding failure mechanism is analysed.The result show that: first,the slope shattering-cracking and relaxed induced by strong earthquake,joint fissures opened and run through; with the shock effect of the seismic forces periodically,the rock-mass fragmentated and disintegrated in the lower part; the high mass has lost support,and the slope overall shattering-slided by the bedding plane eventually.
2010, 18(S1): 482-487.
Landslide hazards triggered by"5.12"WenChuan earthquake have special dynamic process and failure mechanisms,along the fault zone developed many rock block ejection and landslides.This paper is based on the Dazhuping collapse through Beichuan-Yingxiu fault in Gaochuan,by the investigation on the scene,majorly studied the formation mechanism and motion process of a whole ridge and high-speed rock block ejection triggered by Wenchuan earthquake,and according to the actual ejection distance,calculating the topographic amplification horizontal and vertical earthquake acceleration.The results show that under strong earthquake,the structural plane of rock mass cut by cranny by upper throwing force of P-wave and horizontal shear force of S-wave,the surface wave with huge horizontal and vertical acceleration arrives last and is enlarged by terrain,the powerful earthquake force throw the whole rocks to the inclined top,forming collapse,causing a disaster.
Landslide hazards triggered by"5.12"WenChuan earthquake have special dynamic process and failure mechanisms,along the fault zone developed many rock block ejection and landslides.This paper is based on the Dazhuping collapse through Beichuan-Yingxiu fault in Gaochuan,by the investigation on the scene,majorly studied the formation mechanism and motion process of a whole ridge and high-speed rock block ejection triggered by Wenchuan earthquake,and according to the actual ejection distance,calculating the topographic amplification horizontal and vertical earthquake acceleration.The results show that under strong earthquake,the structural plane of rock mass cut by cranny by upper throwing force of P-wave and horizontal shear force of S-wave,the surface wave with huge horizontal and vertical acceleration arrives last and is enlarged by terrain,the powerful earthquake force throw the whole rocks to the inclined top,forming collapse,causing a disaster.
2010, 18(S1): 488-492.
Xinjiang,China has been confronted with a big opportunity to develop since a series supporting programs founded by PRC. Engineering geology and hydrogeology are main branches to solve underground water resources and geologic engineering problems caused by constructions and exploitations in Xinjiang. Basing those demands,the situation of talents needed,educational trend and challenge of long-term progress are analyzed. Furthermore,a typical education and research area is discussed to be taken for one of the keys to make much progress in education and research. Conclusions of the study and deduce are: the number and quality of talents in engineering geology and hydrogeology will increase to adapt to the requirements cause by society expand of Xinjiang; Disequilibrium of educational distribution,deficiencies of teachers,educational surroundings and branches of learning come out with low employment rate and competence,in a another words,the educational/innovative system can not follow the needs of economic and social affairs; Cooperative relations between engineering and environment/geology conditions,such as some engineering geology and hydrogeology problems bring out a higher request to the level of engineering geology and hydrogeology education; the scientific field about engineering geology and hydrogeology problems around snow broth from high mountains,plain of alluvium-diluvium,salt lake/river can be the main characteristic of Xinjiang University to run the specialty of engineering geology and hydrogeology and make scientific effort.
Xinjiang,China has been confronted with a big opportunity to develop since a series supporting programs founded by PRC. Engineering geology and hydrogeology are main branches to solve underground water resources and geologic engineering problems caused by constructions and exploitations in Xinjiang. Basing those demands,the situation of talents needed,educational trend and challenge of long-term progress are analyzed. Furthermore,a typical education and research area is discussed to be taken for one of the keys to make much progress in education and research. Conclusions of the study and deduce are: the number and quality of talents in engineering geology and hydrogeology will increase to adapt to the requirements cause by society expand of Xinjiang; Disequilibrium of educational distribution,deficiencies of teachers,educational surroundings and branches of learning come out with low employment rate and competence,in a another words,the educational/innovative system can not follow the needs of economic and social affairs; Cooperative relations between engineering and environment/geology conditions,such as some engineering geology and hydrogeology problems bring out a higher request to the level of engineering geology and hydrogeology education; the scientific field about engineering geology and hydrogeology problems around snow broth from high mountains,plain of alluvium-diluvium,salt lake/river can be the main characteristic of Xinjiang University to run the specialty of engineering geology and hydrogeology and make scientific effort.
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