It is difficult to obtain reliable shear strength parameters for the stability analysis and evaluation of high loess slopes.Hence,this paper determines slope elements and physical parameter of 79 slopes with heights o...It is difficult to obtain reliable shear strength parameters for the stability analysis and evaluation of high loess slopes.Hence,this paper determines slope elements and physical parameter of 79 slopes with heights of[40,120]m based on the measured loess slopes in the Ganquan and Tonghuang subregions of northern Shaanxi Province,China.In the limit state of the loess slope(stability factor Fs is 1.0),a fitting equation for the slope height and width is established.Then,the model is developed by stability analysis software-SLOPE/W,and the comprehensive shear strength parameters corresponding to different slope heights of the high slope in the study area are obtained by inversion using the Morgenstern-Price method.The results show that when the height of the slope increases,the cohesion c increases in the soil,and the internal friction angle j decreases.This change is consistent with the characteristics reflected in the composition and physical properties of the slopes,and the comprehensive strength parametric curves are very similar between the Ganquan subregion and the Tonghuang subregion.A landslide that occurred in Miaodian-zaitou of Jingyang County,Shaanxi Province,is selected to verify this inversion method,and the results show that the calculated shear strength parameters of the inversion are consistent with the measured value of the actual slope.展开更多
Two branches of Tangjiagou rock avalanche were triggered by Lushan earthquake in Sichuan Province,China on April 20th,2013.The rock avalanche has transported about 1500000 m3 of sandstone from the source area.Based on...Two branches of Tangjiagou rock avalanche were triggered by Lushan earthquake in Sichuan Province,China on April 20th,2013.The rock avalanche has transported about 1500000 m3 of sandstone from the source area.Based on discrete element modeling,this study simulates the deformation,failure and movement process of the rock avalanche.Under seismic loading,the mechanism and process of deformation,failure,and runout of the two branches are similar.In detail,the stress concentration occur firstly on the top of the mountain ridge,and accordingly,the tensile deformation appears.With the increase of seismic loading,the strain concentration zone extends in the forward and backward directions along the slipping surface,forming a locking segment.As a result,the slipping surface penetrates and the slide mass begin to slide down with high speed.Finally,the avalanche accumulates in the downstream and forms a small barrier lake.Modeling shows that a number of rocks on the surface exhibit patterns of horizontal throwing and vertical jumping under strong ground shaking.We suggest that the movement of the rock avalanche is a complicated process with multiple stages,including formation of the two branches,high-speed sliding,transformation into debris flows,further movement and collision,accumulation,and the final steady state.Topographic amplification effects are also revealed based on acceleration and velocity of special monitoring points.The horizontal and vertical runout distances of the surface materials are much greater than those of the internal materials.Besides,the sliding duration is also longer than that of the internal rock mass.展开更多
A large model box was developed in our experiment to study the vibration reduction effect.Five hydraulic highperformance actuators are arranged in the upper part of the model box.There is a time difference between adj...A large model box was developed in our experiment to study the vibration reduction effect.Five hydraulic highperformance actuators are arranged in the upper part of the model box.There is a time difference between adjacent actuators,which can simulate the train induced vibration.To reduce vibration a composite barrier is designed;the barrier consists of a honeycomb concrete canvas and PE polymer water bags.The concrete canvas can be mixed with water to produce a hydration reaction to form a structure with a certain hardness.By simulating different train speeds and loads,vertical vibration velocity,and acceleration before and after the barrier are compared and analyzed.The experimental results show that the new barrier can achieve a good vibration reduction effect.When the simulated train speed increases,the damping effect of the barrier is improved.At a speed of 180 km/h,an amplitude of 1.5 m after the barrier is found to be 48.6%lower than that before the barrier.Velocity decreases by 24.2%at 36 km/h and by 38.1%at 108 km/h.展开更多
For harmful ground collapse and its special deformation characteristics,which causes SAR images to lose coherence,InSAR technology cannot be applied in monitoring surface collapse in mining areas.We took the Shenmu mi...For harmful ground collapse and its special deformation characteristics,which causes SAR images to lose coherence,InSAR technology cannot be applied in monitoring surface collapse in mining areas.We took the Shenmu mining area in northern Shaanxi province as an example to study subsidence in mining areas and proposed an interpolated multi-view processing method.The results show that this method can improve the detectable deformation gradient to a certain extent and can become a good reference value for monitoring large scale gradient deformation.We also analyzed the rules for temporal decorrelation in mining.展开更多
In this paper,an experimental investigation is conducted to study the mechanical behavior of saturated natural loess,saturated natural filling in ground fissure and their corresponding saturated remoulded soils under ...In this paper,an experimental investigation is conducted to study the mechanical behavior of saturated natural loess,saturated natural filling in ground fissure and their corresponding saturated remoulded soils under three consolidated undrained triaxial stress tests,namely,conventional triaxial compression test(CTC),triaxial compression test(TC)and reduced triaxial compression test(RTC).The test results show that stress-strain relation,i.e.strain-softening or strain-hardening,is remarkably influenced by the structure,void ratio,stress path and confining pressure.Natural structure,high void ratio,TC stress path,RTC stress path and low confining pressures are favorable factors leading to strain-softening.Excess pore pressure during shearing is significantly affected by stress path.The tested soils are different from loose sand on character of strain-softening and are different from common clay on excess pore water pressure behavior.The critical states in p′-q space in CTC,TC and RTC tests almost lie on one line,which indicates that the critical state is independent of the above stress paths.As for remoulded loess or remoulded filling,the critical state line(CSL)and isotropic consolidation line(ICL)in e-log p′space are almost straight,while for natural loess or natural filling,in e-log p′space there is a turning point on the CSL,which is similar to the ICL.展开更多
基金supported by National Natural Science Foundation of China(Grant No.41402274,41877242)。
文摘It is difficult to obtain reliable shear strength parameters for the stability analysis and evaluation of high loess slopes.Hence,this paper determines slope elements and physical parameter of 79 slopes with heights of[40,120]m based on the measured loess slopes in the Ganquan and Tonghuang subregions of northern Shaanxi Province,China.In the limit state of the loess slope(stability factor Fs is 1.0),a fitting equation for the slope height and width is established.Then,the model is developed by stability analysis software-SLOPE/W,and the comprehensive shear strength parameters corresponding to different slope heights of the high slope in the study area are obtained by inversion using the Morgenstern-Price method.The results show that when the height of the slope increases,the cohesion c increases in the soil,and the internal friction angle j decreases.This change is consistent with the characteristics reflected in the composition and physical properties of the slopes,and the comprehensive strength parametric curves are very similar between the Ganquan subregion and the Tonghuang subregion.A landslide that occurred in Miaodian-zaitou of Jingyang County,Shaanxi Province,is selected to verify this inversion method,and the results show that the calculated shear strength parameters of the inversion are consistent with the measured value of the actual slope.
基金supported by the NationalNatural Science Foundation of China(41402254)Department of Science and Technology of Shaanxi Province(2019ZDLSF07-0701)。
文摘Two branches of Tangjiagou rock avalanche were triggered by Lushan earthquake in Sichuan Province,China on April 20th,2013.The rock avalanche has transported about 1500000 m3 of sandstone from the source area.Based on discrete element modeling,this study simulates the deformation,failure and movement process of the rock avalanche.Under seismic loading,the mechanism and process of deformation,failure,and runout of the two branches are similar.In detail,the stress concentration occur firstly on the top of the mountain ridge,and accordingly,the tensile deformation appears.With the increase of seismic loading,the strain concentration zone extends in the forward and backward directions along the slipping surface,forming a locking segment.As a result,the slipping surface penetrates and the slide mass begin to slide down with high speed.Finally,the avalanche accumulates in the downstream and forms a small barrier lake.Modeling shows that a number of rocks on the surface exhibit patterns of horizontal throwing and vertical jumping under strong ground shaking.We suggest that the movement of the rock avalanche is a complicated process with multiple stages,including formation of the two branches,high-speed sliding,transformation into debris flows,further movement and collision,accumulation,and the final steady state.Topographic amplification effects are also revealed based on acceleration and velocity of special monitoring points.The horizontal and vertical runout distances of the surface materials are much greater than those of the internal materials.Besides,the sliding duration is also longer than that of the internal rock mass.
基金Supported by:National Natural Science Foundation of China under Grant Nos.52078387 and 51578425the Naturalof Zhejiang Province under Grant No.LY18E080027。
文摘A large model box was developed in our experiment to study the vibration reduction effect.Five hydraulic highperformance actuators are arranged in the upper part of the model box.There is a time difference between adjacent actuators,which can simulate the train induced vibration.To reduce vibration a composite barrier is designed;the barrier consists of a honeycomb concrete canvas and PE polymer water bags.The concrete canvas can be mixed with water to produce a hydration reaction to form a structure with a certain hardness.By simulating different train speeds and loads,vertical vibration velocity,and acceleration before and after the barrier are compared and analyzed.The experimental results show that the new barrier can achieve a good vibration reduction effect.When the simulated train speed increases,the damping effect of the barrier is improved.At a speed of 180 km/h,an amplitude of 1.5 m after the barrier is found to be 48.6%lower than that before the barrier.Velocity decreases by 24.2%at 36 km/h and by 38.1%at 108 km/h.
基金funded by the National Natural Science Foundation of China (Nos.40902081,and 40802075)the Key Project of the Ministry of Land & Resources,China (No.1212010914015)
文摘For harmful ground collapse and its special deformation characteristics,which causes SAR images to lose coherence,InSAR technology cannot be applied in monitoring surface collapse in mining areas.We took the Shenmu mining area in northern Shaanxi province as an example to study subsidence in mining areas and proposed an interpolated multi-view processing method.The results show that this method can improve the detectable deformation gradient to a certain extent and can become a good reference value for monitoring large scale gradient deformation.We also analyzed the rules for temporal decorrelation in mining.
基金supported by China National Funds for Distinguished Young Scientists(No.51025932)the National Natural Science Foundation of China(Grant Nos.10922158 and 40534021the Land and Natural Resources of China(No.1212010914013).
文摘In this paper,an experimental investigation is conducted to study the mechanical behavior of saturated natural loess,saturated natural filling in ground fissure and their corresponding saturated remoulded soils under three consolidated undrained triaxial stress tests,namely,conventional triaxial compression test(CTC),triaxial compression test(TC)and reduced triaxial compression test(RTC).The test results show that stress-strain relation,i.e.strain-softening or strain-hardening,is remarkably influenced by the structure,void ratio,stress path and confining pressure.Natural structure,high void ratio,TC stress path,RTC stress path and low confining pressures are favorable factors leading to strain-softening.Excess pore pressure during shearing is significantly affected by stress path.The tested soils are different from loose sand on character of strain-softening and are different from common clay on excess pore water pressure behavior.The critical states in p′-q space in CTC,TC and RTC tests almost lie on one line,which indicates that the critical state is independent of the above stress paths.As for remoulded loess or remoulded filling,the critical state line(CSL)and isotropic consolidation line(ICL)in e-log p′space are almost straight,while for natural loess or natural filling,in e-log p′space there is a turning point on the CSL,which is similar to the ICL.
