2005 Vol. 13, No. 4

论文
In this paper,the author discusses development strategy of China engineering geology during 11th five-year planning period.After exploring opportunities and challenges in engineering geology,the author outlines scientific problems that engineering geologists needs to address in the future and their role in development of earth system sciences. In this paper,the author discusses development strategy of China engineering geology during 11th five-year planning period.After exploring opportunities and challenges in engineering geology,the author outlines scientific problems that engineering geologists needs to address in the future and their role in development of earth system sciences.
This paper presents the instability mechanisms of a mechanical system that is composed of the stiff hosts(roof and floor) and the coal pillar by using catastrophe theory.It is assumed that the roof is an elastic beam and the coal pillar is a strain-softening medium which can be described by the Weibulls distribution theory of strength.The results indicate that whether the instability can lead to a rockburst largely depends on the systems stiffness ratio k and the homogeneity index m of the coal pillar.A nonlinear dynamical model,which is derived by considering the time-dependent property of the coal pillar,is used to study the physical prediction of rockbursts.An algorithm of inversion on the nonlinear dynamical model is adopted in the search of the precursory abnormality from the observed series of roof settlement.A case study of the Muchengjian coal mine is conducted.Its nonlinear dynamical model is established from the observation series using the algorithm of inversion.An important finding is that the catastrophic characteristic index D drastically increases to a peak value and then quickly drops close to instability.A dynamical model of acoustic emission(AE) is then established based on damage mechanics of coal pillars for modeling the AE activities in the evolutionary process of the system.It is concluded that the values of m and the evolutionary path of the system have a great impact on AE activity patterns and characteristics. This paper presents the instability mechanisms of a mechanical system that is composed of the stiff hosts(roof and floor) and the coal pillar by using catastrophe theory.It is assumed that the roof is an elastic beam and the coal pillar is a strain-softening medium which can be described by the Weibulls distribution theory of strength.The results indicate that whether the instability can lead to a rockburst largely depends on the systems stiffness ratio k and the homogeneity index m of the coal pillar.A nonlinear dynamical model,which is derived by considering the time-dependent property of the coal pillar,is used to study the physical prediction of rockbursts.An algorithm of inversion on the nonlinear dynamical model is adopted in the search of the precursory abnormality from the observed series of roof settlement.A case study of the Muchengjian coal mine is conducted.Its nonlinear dynamical model is established from the observation series using the algorithm of inversion.An important finding is that the catastrophic characteristic index D drastically increases to a peak value and then quickly drops close to instability.A dynamical model of acoustic emission(AE) is then established based on damage mechanics of coal pillars for modeling the AE activities in the evolutionary process of the system.It is concluded that the values of m and the evolutionary path of the system have a great impact on AE activity patterns and characteristics.
The authors present a method for searching for the jump spot of a landslide by generating a detector governed by the rule of partial matching using the algorithm of negative-selection mutation of Artificial Immune System(AIS).A case study for new Wo-long landslide was presented to demonstrate its procedures and applicability. The authors present a method for searching for the jump spot of a landslide by generating a detector governed by the rule of partial matching using the algorithm of negative-selection mutation of Artificial Immune System(AIS).A case study for new Wo-long landslide was presented to demonstrate its procedures and applicability.
In this paper,the authors explored the fractal features of debris flow accumulations,moraine accumulations,alluvial accumulations and residual accumulations at Peilong section along Sichuan-Tibet Highway.According to the fragmentation model and grain size analysis,grain-size fractal dimension were calculated for different types of accumulations.The results showed that fractal dimensions vary for accumulation: the debris flow accumulation with the greatest fractal dimension,the moraine accumulation with the second,residual accumulation with the third,and the alluvial accumulation with the smallest.At the end of the paper,geological significance of grain-size fractal dimension of accumulations was discussed in detail.The grain-size fractal dimension of accumulations reflects the complexity and self-organization property of accumulation,forming process,history of accumulation,and the carrying capacity of the dynamic process,such as debris flow,glacier,river,flood,and so on.Therefore,it can be used as an indictor for classification of accumulations and identification of their origins.This new method is anticipated to provide a better insight into origins of accumulations,which in turn could help gain a better understanding of engineering geological behaviors. In this paper,the authors explored the fractal features of debris flow accumulations,moraine accumulations,alluvial accumulations and residual accumulations at Peilong section along Sichuan-Tibet Highway.According to the fragmentation model and grain size analysis,grain-size fractal dimension were calculated for different types of accumulations.The results showed that fractal dimensions vary for accumulation: the debris flow accumulation with the greatest fractal dimension,the moraine accumulation with the second,residual accumulation with the third,and the alluvial accumulation with the smallest.At the end of the paper,geological significance of grain-size fractal dimension of accumulations was discussed in detail.The grain-size fractal dimension of accumulations reflects the complexity and self-organization property of accumulation,forming process,history of accumulation,and the carrying capacity of the dynamic process,such as debris flow,glacier,river,flood,and so on.Therefore,it can be used as an indictor for classification of accumulations and identification of their origins.This new method is anticipated to provide a better insight into origins of accumulations,which in turn could help gain a better understanding of engineering geological behaviors.
In the pre-feasibility study for the Wudongde Hydropower station,six alternative dam sites,i.e.,Luchelin,Jinshangbao,Hemengkou,Baitan,Santaizi and Wudongde were evaluated.The Reshuitang Fault traverses both the Hemengkou and Baitan dam sites,therefore,it is very important to understand activities of the fault.In order to identify the scale,property and activities of the fault,the authors made a detail analysis of the geomorphologic,lithologic and karstic features along the fault based on interpretation of the aerial photos and field investigation.With geodating and microscopic structural analysis,the authors concluded that the fault was active before middle Pleistocene Epoch,but became less active afterwards and completely ceased after late Pleistocene Epoch.Additional seismic analysis confirmed that Reshsuitang Fault is no longer active. In the pre-feasibility study for the Wudongde Hydropower station,six alternative dam sites,i.e.,Luchelin,Jinshangbao,Hemengkou,Baitan,Santaizi and Wudongde were evaluated.The Reshuitang Fault traverses both the Hemengkou and Baitan dam sites,therefore,it is very important to understand activities of the fault.In order to identify the scale,property and activities of the fault,the authors made a detail analysis of the geomorphologic,lithologic and karstic features along the fault based on interpretation of the aerial photos and field investigation.With geodating and microscopic structural analysis,the authors concluded that the fault was active before middle Pleistocene Epoch,but became less active afterwards and completely ceased after late Pleistocene Epoch.Additional seismic analysis confirmed that Reshsuitang Fault is no longer active.
Secondary stress after excavation could result in deformation of the surrounding rock at Jinping hydropower plant because of deep embedment of the aqueduct tunnel and low compression strength of rock.Therefore,it is an important to appropriately evaluate stability of the deformed surrounding rock.This paper presents a numerical model for evaluating stress state and stability of the deformed surrounding rock under an embedment at a great depth.Two methods: one related to strain ratio and the other related to compression strength,were used to determine locations of deformed surrounding rock and overall stability of the surrounding rock. Secondary stress after excavation could result in deformation of the surrounding rock at Jinping hydropower plant because of deep embedment of the aqueduct tunnel and low compression strength of rock.Therefore,it is an important to appropriately evaluate stability of the deformed surrounding rock.This paper presents a numerical model for evaluating stress state and stability of the deformed surrounding rock under an embedment at a great depth.Two methods: one related to strain ratio and the other related to compression strength,were used to determine locations of deformed surrounding rock and overall stability of the surrounding rock.
Based on the field investigation and experimental data,the authors analyzed geological conditions at an underground plant.Numerical models were developed to well represent the topography,rock mass structure and in-situ stress state.The initial stress condition was estimated using inverse analysis of stress data from in-situ test.With the 3-dimensional elasto-plastic finite difference method,rock mass deformation and stability state of the underground plant were simulated under an asymmetric load.Potential failure and stress concentration were assessed for different excavation stages,which would provide guidelines for a successful completion of the project. Based on the field investigation and experimental data,the authors analyzed geological conditions at an underground plant.Numerical models were developed to well represent the topography,rock mass structure and in-situ stress state.The initial stress condition was estimated using inverse analysis of stress data from in-situ test.With the 3-dimensional elasto-plastic finite difference method,rock mass deformation and stability state of the underground plant were simulated under an asymmetric load.Potential failure and stress concentration were assessed for different excavation stages,which would provide guidelines for a successful completion of the project.
Loess is usually in a saturated state and is called saturated loess when groundwater level is shallow.The 13~(th)、14~(th)、and 15~(th) tunnels of the main canal for the first phase of Yintao Water Supply Project in Gansu pass through saturated loess stratum.The author analyzed the microstructure and chemical composition of saturated loess by comprehensive geotechnical tests and scanning electron-microscope.Based on the derived relationship among its microstructure,the physical-mechanic properties and engineering characteristics,the author recommended that shield method be adopted in excavation of the saturated loess tunnel. Loess is usually in a saturated state and is called saturated loess when groundwater level is shallow.The 13~(th)、14~(th)、and 15~(th) tunnels of the main canal for the first phase of Yintao Water Supply Project in Gansu pass through saturated loess stratum.The author analyzed the microstructure and chemical composition of saturated loess by comprehensive geotechnical tests and scanning electron-microscope.Based on the derived relationship among its microstructure,the physical-mechanic properties and engineering characteristics,the author recommended that shield method be adopted in excavation of the saturated loess tunnel.
Complete stress-strain curves for sandstone,siltstone and mudstone in a red bed slope from east Sichuan province are obtained were obtained under confining pressures from 0 to 3 MPa using MTS815 Teststar,a rock mechanics servo system.The results showed that peak strength,yield strength and relaxation modulus vary with the confining pressure.The complete stress-strain curves can be divided into five phases: compacting,elastic,yield,strain softening and plastic flow.Elasticity modulus of the red bed increases rapidly with the confining pressure.Brittle failure is observed in sandstone and siltstone,while plastic failure is observed in mudstone. Complete stress-strain curves for sandstone,siltstone and mudstone in a red bed slope from east Sichuan province are obtained were obtained under confining pressures from 0 to 3 MPa using MTS815 Teststar,a rock mechanics servo system.The results showed that peak strength,yield strength and relaxation modulus vary with the confining pressure.The complete stress-strain curves can be divided into five phases: compacting,elastic,yield,strain softening and plastic flow.Elasticity modulus of the red bed increases rapidly with the confining pressure.Brittle failure is observed in sandstone and siltstone,while plastic failure is observed in mudstone.
In order to understand the permeability of surrounding rock during post peak unloading of the confining pressure caused by coal mining,the authors conducted permeability test of sandstone using instantaneous permeating method with the electro-hydraulic servo controlled rock mechanics testing system(MTS-815.02).The curves of permeability-axial strain and stress-axial strain before the peak point were obtained.The curves of permeability-confining pressure and principal stress difference-confining pressure during post-peak unloading of confining pressure under a constant axial strain were also obtained.The permeability of sandstone during post-peak unloading of the confining pressure was evaluated by fitting relationship curve of the post-peak permeability-effective confining pressure.The results provide guidelines for solving the problem caused by coupling stress field and seepage field of rock mass in underground engineering. In order to understand the permeability of surrounding rock during post peak unloading of the confining pressure caused by coal mining,the authors conducted permeability test of sandstone using instantaneous permeating method with the electro-hydraulic servo controlled rock mechanics testing system(MTS-815.02).The curves of permeability-axial strain and stress-axial strain before the peak point were obtained.The curves of permeability-confining pressure and principal stress difference-confining pressure during post-peak unloading of confining pressure under a constant axial strain were also obtained.The permeability of sandstone during post-peak unloading of the confining pressure was evaluated by fitting relationship curve of the post-peak permeability-effective confining pressure.The results provide guidelines for solving the problem caused by coupling stress field and seepage field of rock mass in underground engineering.
Dynamic compaction method is an easy and rapid construction method that has been widely used in China and around theworld because it does not cause any environmental pollution.This paper presents the analytical analysis of settlement before foundationreatment,design of dynamic compaction、construction procedures and implementation(arts and crafts) of dynamic compaction as wellas associated problems encountered in construction. Dynamic compaction method is an easy and rapid construction method that has been widely used in China and around theworld because it does not cause any environmental pollution.This paper presents the analytical analysis of settlement before foundationreatment,design of dynamic compaction、construction procedures and implementation(arts and crafts) of dynamic compaction as wellas associated problems encountered in construction.
Stability of rock engineering is greatly affected by joints.The shear strength of the joints is a controlling parameter in analysis of rock mass stability.In this paper,authors presented an average slope method for a quick and an accurate estimate of shear strength of joints,based on review of the JRC-JCS model and several other existing methods.Its advantages over other methods were demonstrated by case studies. Stability of rock engineering is greatly affected by joints.The shear strength of the joints is a controlling parameter in analysis of rock mass stability.In this paper,authors presented an average slope method for a quick and an accurate estimate of shear strength of joints,based on review of the JRC-JCS model and several other existing methods.Its advantages over other methods were demonstrated by case studies.
This paper characterized the monitored ground temperature of the frozen soil embankment with riprap slope protection and the normal embankment in Qingshuihe test section along Qinghai-Tibet railway.The ground temperature data inside the embankment and at the bottom of base were compared for these two kinds of embankment.The results showed that the experimental embankment with riprap protection performs better in lowering temperature,lowering minus accumulated temperature and reducing maximum thawing depth than the common embankment.Therefore,the embankment with riprap slope protection could provide permafrost protection by effectively decreasing ground temperature. This paper characterized the monitored ground temperature of the frozen soil embankment with riprap slope protection and the normal embankment in Qingshuihe test section along Qinghai-Tibet railway.The ground temperature data inside the embankment and at the bottom of base were compared for these two kinds of embankment.The results showed that the experimental embankment with riprap protection performs better in lowering temperature,lowering minus accumulated temperature and reducing maximum thawing depth than the common embankment.Therefore,the embankment with riprap slope protection could provide permafrost protection by effectively decreasing ground temperature.
This present a case study of a non-linear three-dimensional finite element method in analysis of the dynamic excavating process of an underground cavern and optimization of excavating sequence and span.The model was developed for an underground cavern of Gejiu Tin Mine of Yunnan Tin Corporation to optimize its operation under current conditions. This present a case study of a non-linear three-dimensional finite element method in analysis of the dynamic excavating process of an underground cavern and optimization of excavating sequence and span.The model was developed for an underground cavern of Gejiu Tin Mine of Yunnan Tin Corporation to optimize its operation under current conditions.
To enhance automatization in the design of reservoirs and three dimensional visualization of its model,this paper presents a modeling method for three dimensional terrains and its application in design of a reservoir.Terrain fidelity of digital elevation model(DEM) can be enhanced by integrating terrain character points and terrain lines in the three dimensional model.A synthetic removal method for integrated horizontal line and covering hidings allows us to completely remove hidings and fast build images.With three dimensional model of reservoir,one can not only estimate the reservoir capacity,flooding borderline and flooding area of reservoir water,but also generate the terrain profiles.Integrated profiles can also be developed by overlaying geological maps,hydrological maps and tectonic maps on the terrain profiles.At the end,the design of a reservoir is simulated using three dimensional visualization technique.The results show that the three dimensional terrain model provides a simple tool for selecting the dam site,determining reservoir capacity,and estimating water level of reservoir. To enhance automatization in the design of reservoirs and three dimensional visualization of its model,this paper presents a modeling method for three dimensional terrains and its application in design of a reservoir.Terrain fidelity of digital elevation model(DEM) can be enhanced by integrating terrain character points and terrain lines in the three dimensional model.A synthetic removal method for integrated horizontal line and covering hidings allows us to completely remove hidings and fast build images.With three dimensional model of reservoir,one can not only estimate the reservoir capacity,flooding borderline and flooding area of reservoir water,but also generate the terrain profiles.Integrated profiles can also be developed by overlaying geological maps,hydrological maps and tectonic maps on the terrain profiles.At the end,the design of a reservoir is simulated using three dimensional visualization technique.The results show that the three dimensional terrain model provides a simple tool for selecting the dam site,determining reservoir capacity,and estimating water level of reservoir.
In stability analysis of embankment reinforced by geosynthetics,the traditional method,such as Sweden method and Hollands method,is obviously conservative owing to underestimation of reinforcement effect of geosynthetics.The authors present a new stability analysis method of embankment reinforced by geosynthetics by modifying assumption of reinforcements effect.In addition,the niche genetic algorithm(NGA) is applied in searching for critical slip surface of reinforced embankment.Two case studies were used to demonstrate effectiveness and applicability of the presented method. In stability analysis of embankment reinforced by geosynthetics,the traditional method,such as Sweden method and Hollands method,is obviously conservative owing to underestimation of reinforcement effect of geosynthetics.The authors present a new stability analysis method of embankment reinforced by geosynthetics by modifying assumption of reinforcements effect.In addition,the niche genetic algorithm(NGA) is applied in searching for critical slip surface of reinforced embankment.Two case studies were used to demonstrate effectiveness and applicability of the presented method.
This paper analyzed mechanical behavior and failure mechanism of a flexible abutment reinforced by geotextiles by using finite element method in consideration of consolidation and non-linear constitutive relation of soil.The reinforced soil was simulated as a three-layer material consisting of soil,geotextile,and interface between them.The results indicated that the reinforcement could reduce its uniform settlement by 50% and differential settlement by 66%.It,could also improve the embankments stability. This paper analyzed mechanical behavior and failure mechanism of a flexible abutment reinforced by geotextiles by using finite element method in consideration of consolidation and non-linear constitutive relation of soil.The reinforced soil was simulated as a three-layer material consisting of soil,geotextile,and interface between them.The results indicated that the reinforcement could reduce its uniform settlement by 50% and differential settlement by 66%.It,could also improve the embankments stability.
This paper presents results of the wall rock resistance,the lining-stress,distortion and stability of XinDaoGou double vault tunnel along Beijing-Chengde highway using the finite element method.The model was developed based on structure of double vault lining with the wall rock resistance which is simulated by elasticity pole cell.In addition,the secondary lining strength in maximal measured-stress face is checked against design specification of high way tunnel.Such results provide guidelines for the optimizing design of XinDaoGou tunnel. This paper presents results of the wall rock resistance,the lining-stress,distortion and stability of XinDaoGou double vault tunnel along Beijing-Chengde highway using the finite element method.The model was developed based on structure of double vault lining with the wall rock resistance which is simulated by elasticity pole cell.In addition,the secondary lining strength in maximal measured-stress face is checked against design specification of high way tunnel.Such results provide guidelines for the optimizing design of XinDaoGou tunnel.
The seismic wave travels at different velocities in different media,therefore the seismic wave can be used to detect effects of grouting engineering.The paper presents a case study of its application in detecting effects of grouting in Da-ping rock pile.By comparing difference in compression modulus before and after grouting and detection of seismic waves,the authors concluded that the seismic wave method is a good method for detecting effects of grouting in highway slopes. The seismic wave travels at different velocities in different media,therefore the seismic wave can be used to detect effects of grouting engineering.The paper presents a case study of its application in detecting effects of grouting in Da-ping rock pile.By comparing difference in compression modulus before and after grouting and detection of seismic waves,the authors concluded that the seismic wave method is a good method for detecting effects of grouting in highway slopes.
Frozen ground made a complex mechanical state of the pile-supported foundation pit of the Runyang Bridge.To assure its stability,a large safety monitoring system was established based on structure characteristics of frozen ground and pile-support deep foundation pit,and the engineering geological condition of site.This paper presents monitoring data including lateral earth pressure,inner support forces,stresses and displacements,and their analysis.A feedback analysis was made based on the monitoring data..The monitor result indicated the ground freezing and pile-support method is viable for deep foundation pit,and the experience was backlog for construction of similar engineering aftertime. Frozen ground made a complex mechanical state of the pile-supported foundation pit of the Runyang Bridge.To assure its stability,a large safety monitoring system was established based on structure characteristics of frozen ground and pile-support deep foundation pit,and the engineering geological condition of site.This paper presents monitoring data including lateral earth pressure,inner support forces,stresses and displacements,and their analysis.A feedback analysis was made based on the monitoring data..The monitor result indicated the ground freezing and pile-support method is viable for deep foundation pit,and the experience was backlog for construction of similar engineering aftertime.
ased on slope stability analysis of the embankment along National Highway No.108 k15+760~+980,the authors analyzed mechanisms of deformation and failure and its reinforcement treatment.By monitoring displacement of embankment and settlement of road surface,the authors characterized the patterns of the surface movement and the embankment settlement and their dynamics under unstable conditions,which would provide guidelines for control of embankment displacement during the construction and in turn assure slope stability. ased on slope stability analysis of the embankment along National Highway No.108 k15+760~+980,the authors analyzed mechanisms of deformation and failure and its reinforcement treatment.By monitoring displacement of embankment and settlement of road surface,the authors characterized the patterns of the surface movement and the embankment settlement and their dynamics under unstable conditions,which would provide guidelines for control of embankment displacement during the construction and in turn assure slope stability.
In order to assess stability of Longpan right bank slope in the Hutiao Gorge,the authors use geophysical method such as CSAMT to characterize structure and patterns of the slope.With geological information,the distribution of deformation bodies,their scales and internal non-uniform structures were obtained.This study will not only demonstrate physical constraints for characterizing deformation bodies,but also provide geophysical verification of stability of deformation bodies and potential geological hazards. In order to assess stability of Longpan right bank slope in the Hutiao Gorge,the authors use geophysical method such as CSAMT to characterize structure and patterns of the slope.With geological information,the distribution of deformation bodies,their scales and internal non-uniform structures were obtained.This study will not only demonstrate physical constraints for characterizing deformation bodies,but also provide geophysical verification of stability of deformation bodies and potential geological hazards.
EH4 electromagnetic image system is a set of dual-power electromagnetic auto collecting and processing geophysical exploration system. It is a combination of CSAMT and MT.The paper describes principles,characteristics,procedures and data analysis of EH4 using a case study in survey and investigation of the deeply-buried long tunnel in Expressway in Yunnan.EH4 successfully located soft and weak layer,underground water and broken fractures with assistance of other technical methods,which provides additional information needed for classification of surrounding rocks of the tunnel.This method also provides a new method for survey of deeply-buried long highway tunnels. EH4 electromagnetic image system is a set of dual-power electromagnetic auto collecting and processing geophysical exploration system. It is a combination of CSAMT and MT.The paper describes principles,characteristics,procedures and data analysis of EH4 using a case study in survey and investigation of the deeply-buried long tunnel in Expressway in Yunnan.EH4 successfully located soft and weak layer,underground water and broken fractures with assistance of other technical methods,which provides additional information needed for classification of surrounding rocks of the tunnel.This method also provides a new method for survey of deeply-buried long highway tunnels.
This paper discusses mechanisms and technical parameters of structure reinforced by grouting with an engineering case study.Jet grouting parameters and their influence on the design parameters such as grout grading,layout of grouting holes,grouting depth,grouting capacity and grouting pressure were discussed.Importance of dynamic control during the construction was emphasized.Monitoring results and analysis show that the two-shot grouting combining complementary jet grouting was effective and feasible way to rectify and reinforce a non-uniform settlement building. This paper discusses mechanisms and technical parameters of structure reinforced by grouting with an engineering case study.Jet grouting parameters and their influence on the design parameters such as grout grading,layout of grouting holes,grouting depth,grouting capacity and grouting pressure were discussed.Importance of dynamic control during the construction was emphasized.Monitoring results and analysis show that the two-shot grouting combining complementary jet grouting was effective and feasible way to rectify and reinforce a non-uniform settlement building.
The intake slope of enlargement project of Fentan Hydropower Station is a thick-layered slope of good quality that dips backward.However,slightly toppling deformation occurred on the slope over the intake tunnels because of unsupported excavation of the slope and intake tunnels.This paper described the engineering geological conditions associated with the intake slope and analyzed stability of the thick-layered rock slope over the intake tunnels. The causes for slightly toppling due to excavation were analyzed and appropriate stabilization measures proposed.The field monitoring data show that the rock slope was stable after treatment. The intake slope of enlargement project of Fentan Hydropower Station is a thick-layered slope of good quality that dips backward.However,slightly toppling deformation occurred on the slope over the intake tunnels because of unsupported excavation of the slope and intake tunnels.This paper described the engineering geological conditions associated with the intake slope and analyzed stability of the thick-layered rock slope over the intake tunnels. The causes for slightly toppling due to excavation were analyzed and appropriate stabilization measures proposed.The field monitoring data show that the rock slope was stable after treatment.
Soil model parameters are critical in assuring reliability of numerical results of commonly used finite element method for simulating settlement of embankment.The Duncan-Chang E-B model,a nonlinear elastic model widely used in the geotechnical engineering,was chosen in this paper.Based on the sensitivity analysis of model parameters,relationships of various parameters with vertical embankment settlement and lateral displacement were obtained. The critical parameters were also determined based on the sensitivity analysis. Soil model parameters are critical in assuring reliability of numerical results of commonly used finite element method for simulating settlement of embankment.The Duncan-Chang E-B model,a nonlinear elastic model widely used in the geotechnical engineering,was chosen in this paper.Based on the sensitivity analysis of model parameters,relationships of various parameters with vertical embankment settlement and lateral displacement were obtained. The critical parameters were also determined based on the sensitivity analysis.
In this paper authors characterized stress and loading mechanism of pre-stressed anchor-rod cross coupling in supporting deep foundation pit.Finite element method is used to simulate stress distribution in foundation pit supported by such beam.The moment of flexure of the beam and displacement of surface layer are also calculated,which overcomes disadvantage of traditional methods.By comparing simulated results with traditional anchor-pile supporting method the authors concluded that it is an economic and reliable way to apply pre-stressed anchor-rod cross coupling when the end of slope-protection pile cant be driven into the foundation. In this paper authors characterized stress and loading mechanism of pre-stressed anchor-rod cross coupling in supporting deep foundation pit.Finite element method is used to simulate stress distribution in foundation pit supported by such beam.The moment of flexure of the beam and displacement of surface layer are also calculated,which overcomes disadvantage of traditional methods.By comparing simulated results with traditional anchor-pile supporting method the authors concluded that it is an economic and reliable way to apply pre-stressed anchor-rod cross coupling when the end of slope-protection pile cant be driven into the foundation.