A large-scale test bed(LWH=6 m×3 m×2.8 m)instrumented with various sensors is used to examine the effects of rainfall infiltration and evaporation on the deformation and failure of cracked soil slopes,taking...A large-scale test bed(LWH=6 m×3 m×2.8 m)instrumented with various sensors is used to examine the effects of rainfall infiltration and evaporation on the deformation and failure of cracked soil slopes,taking the Anhui area along the Yangtze River as a field example.The results indicate that(1)during rainfall,the soil around the shallow shrinkage fissures attains transient saturation,and the attendant decrease of matric suction is the primary cause of the shallow slope failure;(2)slope deformation continues during post-rainfall evaporation;(3)if a period of evaporation is followed by heavy rainfall,soil creep is concentrated near the deepest cracks,and two zones of steep gradients in pore pressure form at the crest and toe of the slope.Finally,a saturated zone forms near each crack base and gradually enlarges,eventually forming a continuous saturated layer that induces the slope instability or failure.展开更多
The Sanandaj-Sirjan metamorphic zone experienced a polyphase deformation history,which is related to the Zagros orogenic belt.At the northwestern part of Sanandaj-Sirjan zone many pegmatoied dykes intruded in
In the early hours of June 24,2017,a major landslide event occurred in Xinmo Village,Sichuan Province,China.The landslide instantly devastated the whole village.Ten people died and 73 were missing in this major landsl...In the early hours of June 24,2017,a major landslide event occurred in Xinmo Village,Sichuan Province,China.The landslide instantly devastated the whole village.Ten people died and 73 were missing in this major landslide event.The study area has suffered from several strong earthquakes in the past 100 y.Present studies have reported that the cumulative damage effect of the Xinmo landslide induced by earthquake is obvious.In this study,we conducted a shaking table test based on the detailed geological survey,historical seismic data,satellite optical image,unmanned aerial vehicle photography.The test result presents the characteristics of multistage seismic damage and progressive deformation process of the Xinmo landslide model,and shows that the historical earthquakes have caused serious damage to the interior of rock mass in the source area.The test also shows that the cumulative damage of the model increases with an increase in duration of earthquake loading.When the excitation intensity increases to a certain value,the damage accumulation velocity of the model suddenly increases.It reveals that frequent historical earthquake loads can be regarded as a main reason for the damage and deterioration of landslide rock mass.Damage accumulation and superposition occur in the slope.Under a long-term gravity,deformation of the slope gradually increases until catastrophic failure is triggered.The progressive deformation process of slope is summarized.Firstly,under strong earthquakes loading,a tensile fracture surface forms at the rear edge of the wavy deformation high and steep bedding slope.It reaches a certain critical depth and expands along the interlayer structural plane.Meantime,damaged fissures perpendicular to the structural plane also appear in the steep-gentle turning area of the slope.Secondly,under a coupling action of seismic loading and gravity,the interlaminar tensile crack surface at the rear edge of the slope extends to depth continuously.Meanwhile,rock fracture occurs in the steep-gentle turning area.The“two-way damage propagation”mode of the interlayer tensile crack surface occurs until the sliding surface is connected.However,due to the“locking section”effect of rock mass at the slope foot,it can still maintain a short-term stability.Thirdly,under the influences of the heavy rainfall before a landslide and the long-term gravity of the upper sliding mass,rock mass in the steep section at the slope foot breaks outward.Finally,a catastrophic landslide occurs.展开更多
Assessing the slope deformation is significant for landslide prediction. Many researchers have studied the slope displacement based on field data from the inclinometer in combination with complicated numerical analysi...Assessing the slope deformation is significant for landslide prediction. Many researchers have studied the slope displacement based on field data from the inclinometer in combination with complicated numerical analysis. They found that there was a shear zone above the slip surface, and they usually focused on the distribution of velocity and displacement within the shear zone. In this paper,two simple methods are proposed to analyze the distribution of displacement and velocity along the whole profile of a slope from the slip surface to the slope surface during slow movement. In the empirical method, the slope soil above the shear zone is assumed as a rigid body. Dual or triple piecewise fitting functions are empirically proposed for the distribution of velocity along the profile of a slope. In the analytical method, the slope soil is not assumed as a rigid body but as a deformable material. Continuous functions of the velocity and displacement along the profile of a slope are directly obtained by solving the Newton's equation of motion associated with the Bingham model. Using the two proposed methods respectively, the displacement and velocity along the slope profiles of three slopes are determined. A reasonable agreement between the measured data and the calculated results of the two proposed methods has been reached. In comparison with the empirical method, the analytical method would be more beneficial for slope deformation analysis in slope engineering, because the parameters are material constants in the analytical solution independent of time t, and the nonlinear viscosity of the soil can be considered.展开更多
This paper discusses the tectonic divisions of the Himalayan collision belt anddeals with the tectonic evolution of the collision belt in the context of crustal accretion in thefront of the collision belt, deep diapir...This paper discusses the tectonic divisions of the Himalayan collision belt anddeals with the tectonic evolution of the collision belt in the context of crustal accretion in thefront of the collision belt, deep diapirism and thermal-uplift extension and deep material flow-ing of the lithosphere-backflowing. Finally it proposes a model of the tectonic evolution-progressive intracontinental deformation model-of the Himalayan belt.展开更多
基金the scope of the project of Anhui Province Transport Technology Progress Plan(Nos.2018030,JKKJ-2020)funded by the Fundamental Research Funds for Central Universities,China University of Geosciences(Wuhan)(Nos.1810491A24,CUG160203)the Opening Fund of the Key Laboratory of Geological Survey and Evaluation of Ministry of Education of China(No.GLAB2019 ZR05)。
文摘A large-scale test bed(LWH=6 m×3 m×2.8 m)instrumented with various sensors is used to examine the effects of rainfall infiltration and evaporation on the deformation and failure of cracked soil slopes,taking the Anhui area along the Yangtze River as a field example.The results indicate that(1)during rainfall,the soil around the shallow shrinkage fissures attains transient saturation,and the attendant decrease of matric suction is the primary cause of the shallow slope failure;(2)slope deformation continues during post-rainfall evaporation;(3)if a period of evaporation is followed by heavy rainfall,soil creep is concentrated near the deepest cracks,and two zones of steep gradients in pore pressure form at the crest and toe of the slope.Finally,a saturated zone forms near each crack base and gradually enlarges,eventually forming a continuous saturated layer that induces the slope instability or failure.
文摘The Sanandaj-Sirjan metamorphic zone experienced a polyphase deformation history,which is related to the Zagros orogenic belt.At the northwestern part of Sanandaj-Sirjan zone many pegmatoied dykes intruded in
基金financially supported by the National Natural Science Foundation of China(No.42377194)the Sichuan Science and Technology Program(No.2023NSFSC0282)+1 种基金the Sichuan Province Central Government Guides Local Science and Technology Development Special Project(No.2023ZYD0151)the State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Independent Research Project(No.SKLGP2021Z008)。
文摘In the early hours of June 24,2017,a major landslide event occurred in Xinmo Village,Sichuan Province,China.The landslide instantly devastated the whole village.Ten people died and 73 were missing in this major landslide event.The study area has suffered from several strong earthquakes in the past 100 y.Present studies have reported that the cumulative damage effect of the Xinmo landslide induced by earthquake is obvious.In this study,we conducted a shaking table test based on the detailed geological survey,historical seismic data,satellite optical image,unmanned aerial vehicle photography.The test result presents the characteristics of multistage seismic damage and progressive deformation process of the Xinmo landslide model,and shows that the historical earthquakes have caused serious damage to the interior of rock mass in the source area.The test also shows that the cumulative damage of the model increases with an increase in duration of earthquake loading.When the excitation intensity increases to a certain value,the damage accumulation velocity of the model suddenly increases.It reveals that frequent historical earthquake loads can be regarded as a main reason for the damage and deterioration of landslide rock mass.Damage accumulation and superposition occur in the slope.Under a long-term gravity,deformation of the slope gradually increases until catastrophic failure is triggered.The progressive deformation process of slope is summarized.Firstly,under strong earthquakes loading,a tensile fracture surface forms at the rear edge of the wavy deformation high and steep bedding slope.It reaches a certain critical depth and expands along the interlayer structural plane.Meantime,damaged fissures perpendicular to the structural plane also appear in the steep-gentle turning area of the slope.Secondly,under a coupling action of seismic loading and gravity,the interlaminar tensile crack surface at the rear edge of the slope extends to depth continuously.Meanwhile,rock fracture occurs in the steep-gentle turning area.The“two-way damage propagation”mode of the interlayer tensile crack surface occurs until the sliding surface is connected.However,due to the“locking section”effect of rock mass at the slope foot,it can still maintain a short-term stability.Thirdly,under the influences of the heavy rainfall before a landslide and the long-term gravity of the upper sliding mass,rock mass in the steep section at the slope foot breaks outward.Finally,a catastrophic landslide occurs.
基金supported by the National Natural Science Foundation of China(Grant No.51579167)the Public Non-profit Welfare Project from China Ministry of Water Resources(Grant No.201301022)the Key Laboratory of Failure Mechanism and Safety Control Techniques of Earth-rock Dam of the Ministry of Water Resources(Grant No.YK915003)
文摘Assessing the slope deformation is significant for landslide prediction. Many researchers have studied the slope displacement based on field data from the inclinometer in combination with complicated numerical analysis. They found that there was a shear zone above the slip surface, and they usually focused on the distribution of velocity and displacement within the shear zone. In this paper,two simple methods are proposed to analyze the distribution of displacement and velocity along the whole profile of a slope from the slip surface to the slope surface during slow movement. In the empirical method, the slope soil above the shear zone is assumed as a rigid body. Dual or triple piecewise fitting functions are empirically proposed for the distribution of velocity along the profile of a slope. In the analytical method, the slope soil is not assumed as a rigid body but as a deformable material. Continuous functions of the velocity and displacement along the profile of a slope are directly obtained by solving the Newton's equation of motion associated with the Bingham model. Using the two proposed methods respectively, the displacement and velocity along the slope profiles of three slopes are determined. A reasonable agreement between the measured data and the calculated results of the two proposed methods has been reached. In comparison with the empirical method, the analytical method would be more beneficial for slope deformation analysis in slope engineering, because the parameters are material constants in the analytical solution independent of time t, and the nonlinear viscosity of the soil can be considered.
基金This study was a part of the Project Research on Deformation Dynamics on the North Margin of the Qinghai-Tibet Plateau(No,86-06-207)- a key Project of deep geology of the Ministry of Geology and Mineral Resources in the Eighth Five-Year Plan period(1991
文摘This paper discusses the tectonic divisions of the Himalayan collision belt anddeals with the tectonic evolution of the collision belt in the context of crustal accretion in thefront of the collision belt, deep diapirism and thermal-uplift extension and deep material flow-ing of the lithosphere-backflowing. Finally it proposes a model of the tectonic evolution-progressive intracontinental deformation model-of the Himalayan belt.
