With the construction of the Xiluodu hydropower station on the Jinsha River,the reservoir impoundment began in 2013 and the water level fluctuates annually between 540 m and 600 m above sea level.The Yanjiao rock slop...With the construction of the Xiluodu hydropower station on the Jinsha River,the reservoir impoundment began in 2013 and the water level fluctuates annually between 540 m and 600 m above sea level.The Yanjiao rock slope which is located on the left bank of the Jinsha River 75 km upstream of the Xiluodu dam site,began to deform in 2014.The potential failure of the slope not only threatens Yanjiao town but also affects the safe operation of the Xiluodu reservoir.This paper is to find the factors influencing the Yanjiao slope deformation through field investigation,geotechnical reconnaissance,and monitoring.Results show that the Yanjiao slope can be divided into a bank collapse area(BCA)and a strong deformation area(SDA)based on the crack distribution characteristics of the slope.The rear area of the slope has been experiencing persistent deformation with a maximum cumulative displacement(GPS monitoring point G4)of 505 mm and 399 mm in the horizontal and vertical directions,respectively.The potential failure surface of the slope is formed 36 m below the surface based on the borehole inclinometer.The bank collapses of the Yanjiao slope are directly caused by the reservoir impoundment while the deformation area of the slope is affected by the combination of the rainfall and reservoir water level fluctuation.Based on mechanism of the Yanjiao slope,prestressed anchor combined with the surface drainage and slope unloading are recommended to prevent potential deformation.展开更多
Frequent soil landslide events are recorded in the Three Gorges Reservoir area,China,making it necessary to investigate the failure mode of such riverside landslides.Geotechnical centrifugal test is considered to be t...Frequent soil landslide events are recorded in the Three Gorges Reservoir area,China,making it necessary to investigate the failure mode of such riverside landslides.Geotechnical centrifugal test is considered to be the most realistic laboratory model,which can reconstruct the required geo-stress.In this study,the Liangshuijing landslide in the Three Gorgers Reservoir area is selected for a scaled centrifugal model experiment,and a water pump system is employed to retain the rainfall condition.Using the techniques of digital photography and pore water pressure transducers,water level fluctuation is controlled,and multi-physical data are thus obtained,including the pore water pressure,earth pressure,surface displacement and deep displacement.The analysis results indicate that:Three stages were set in the test(waterflooding stage,rainfall stage and drainage stage).Seven transverse cracks with wide of 1–5 mm appeared during the model test,of which 3 cracks at the toe landslide were caused by reservoir water fluctuation,and the cracks at the middle and rear part were caused by rainfall.During rainfall process,the maximum displacement of landslide model reaches 3 cm.And the maximum deformation of the model exceeds 12 cm at the drainage stage.The failure process of the slope model can be divided into four stages:microcracks appearance and propagation stage,thrust-type failure stage,retrogressive failure stage,and holistic failure stage.When the thrust-type zone caused by rainfall was connected or even overlapped with the retrogressive failure zone caused by the drainage,the landslide would start,which displayed a typical composite failure pattern.The failure mode and deformation mechanism under the coupling actions of water level fluctuation and rainfall are revealed in the model test,which could appropriately guide for the analysis and evaluation of riverside landslides.展开更多
Landslide is a common geological hazard in reservoir areas and may cause great damage to local residents’life and property.It is widely accepted that rainfall and periodic variation of water level are the two main fa...Landslide is a common geological hazard in reservoir areas and may cause great damage to local residents’life and property.It is widely accepted that rainfall and periodic variation of water level are the two main factors triggering reservoir landslides.In this study,the Bazimen landslide located in the Three Gorges Reservoir(TGR)was back-analyzed as a case study.Based on the statistical features of the last 3-year monitored data and field instrumentations,the landslide susceptibility in an annual cycle and four representative periods was investigated via the deterministic and probabilistic analysis,respectively.The results indicate that the fluctuation of the reservoir water level plays a pivotal role in inducing slope failures,for the minimum stability coefficient occurs at the rapid decline period of water level.The probabilistic analysis results reveal that the initial sliding surface is the most important area influencing the occurrence of landslide,compared with other parts in the landslide.The seepage calculations from probabilistic analysis imply that rainfall is a relatively inferior factor affecting slope stability.This study aims to provide preliminary guidance on risk management and early warning in the TGR area.展开更多
This study focuses on the deformation characteristics of Kadui-2 Landslide by the influence of reservoir filling-drawdown and precipitation.A three-year monitoring project was implemented in order to observe the short...This study focuses on the deformation characteristics of Kadui-2 Landslide by the influence of reservoir filling-drawdown and precipitation.A three-year monitoring project was implemented in order to observe the short/long-term deformation.The slide mass experienced consistent deformation with a maximum cumulative displacement of 331.34 cm.Based on the recorded data of reservoir water level and precipitation during this period,a two-dimensional(2-D)finite element model using Geostudio software was set up for deformation simulation under different conditions to understand the real influence of these triggering factors on landslide.The numerical simulation results are in consistent with monitoring field data.Both numerical simulation and field monitoring results exhibit that the maximum deformation occurred at the foreside of slumping mass.The slip surface shows significant creep characteristics decreasing as long-term shear strength reducing gradually.Reservoir water level fluctuation is the primary triggering factor to reactivate the landslide mass and has a negative correlation with deformation rate.Displacement rate increases with the reservoir drawdown and decreases with impoundment rise.Compared with reservoir filling-drawdown operation,rainfall has no significant effect on the slide motion of landslide due to limited penetration from the ground surface.展开更多
基金the project of POWERCHINA Chengdu Engineering Corporation Limited,Power China under Grant No.P46220the Natural Science Foundation of Sichuan,China under Grant No.2022NSFSC0425the Science and Technology Department of Sichuan Province under Grant No.2021YJ0053。
文摘With the construction of the Xiluodu hydropower station on the Jinsha River,the reservoir impoundment began in 2013 and the water level fluctuates annually between 540 m and 600 m above sea level.The Yanjiao rock slope which is located on the left bank of the Jinsha River 75 km upstream of the Xiluodu dam site,began to deform in 2014.The potential failure of the slope not only threatens Yanjiao town but also affects the safe operation of the Xiluodu reservoir.This paper is to find the factors influencing the Yanjiao slope deformation through field investigation,geotechnical reconnaissance,and monitoring.Results show that the Yanjiao slope can be divided into a bank collapse area(BCA)and a strong deformation area(SDA)based on the crack distribution characteristics of the slope.The rear area of the slope has been experiencing persistent deformation with a maximum cumulative displacement(GPS monitoring point G4)of 505 mm and 399 mm in the horizontal and vertical directions,respectively.The potential failure surface of the slope is formed 36 m below the surface based on the borehole inclinometer.The bank collapses of the Yanjiao slope are directly caused by the reservoir impoundment while the deformation area of the slope is affected by the combination of the rainfall and reservoir water level fluctuation.Based on mechanism of the Yanjiao slope,prestressed anchor combined with the surface drainage and slope unloading are recommended to prevent potential deformation.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41977244, 42007267)the National Key R&D Program of China (Grant No. 2017YFC1501301)
文摘Frequent soil landslide events are recorded in the Three Gorges Reservoir area,China,making it necessary to investigate the failure mode of such riverside landslides.Geotechnical centrifugal test is considered to be the most realistic laboratory model,which can reconstruct the required geo-stress.In this study,the Liangshuijing landslide in the Three Gorgers Reservoir area is selected for a scaled centrifugal model experiment,and a water pump system is employed to retain the rainfall condition.Using the techniques of digital photography and pore water pressure transducers,water level fluctuation is controlled,and multi-physical data are thus obtained,including the pore water pressure,earth pressure,surface displacement and deep displacement.The analysis results indicate that:Three stages were set in the test(waterflooding stage,rainfall stage and drainage stage).Seven transverse cracks with wide of 1–5 mm appeared during the model test,of which 3 cracks at the toe landslide were caused by reservoir water fluctuation,and the cracks at the middle and rear part were caused by rainfall.During rainfall process,the maximum displacement of landslide model reaches 3 cm.And the maximum deformation of the model exceeds 12 cm at the drainage stage.The failure process of the slope model can be divided into four stages:microcracks appearance and propagation stage,thrust-type failure stage,retrogressive failure stage,and holistic failure stage.When the thrust-type zone caused by rainfall was connected or even overlapped with the retrogressive failure zone caused by the drainage,the landslide would start,which displayed a typical composite failure pattern.The failure mode and deformation mechanism under the coupling actions of water level fluctuation and rainfall are revealed in the model test,which could appropriately guide for the analysis and evaluation of riverside landslides.
基金This work was supported by the Natural Science Foundation of Chongqing,China(Nos.cstc2018jcyjAX0632 and cstc2019jcyj-bshX0043)the High-end Foreign Expert Introduction program(No.G20190022002)+1 种基金Chongqing Engineering Research Center of Disaster Prevention&Control for Banks and Structures in Three Gorges Reservoir Area(Nos.SXAPGC18ZD01 and SXAPGC18YB03)The financial support is gratefully acknowledged.The monitored data and historical records used in this study is from the Chinese National Field Scientific Observation Station of Landslide in The Yangtze Threc Gorges.
文摘Landslide is a common geological hazard in reservoir areas and may cause great damage to local residents’life and property.It is widely accepted that rainfall and periodic variation of water level are the two main factors triggering reservoir landslides.In this study,the Bazimen landslide located in the Three Gorges Reservoir(TGR)was back-analyzed as a case study.Based on the statistical features of the last 3-year monitored data and field instrumentations,the landslide susceptibility in an annual cycle and four representative periods was investigated via the deterministic and probabilistic analysis,respectively.The results indicate that the fluctuation of the reservoir water level plays a pivotal role in inducing slope failures,for the minimum stability coefficient occurs at the rapid decline period of water level.The probabilistic analysis results reveal that the initial sliding surface is the most important area influencing the occurrence of landslide,compared with other parts in the landslide.The seepage calculations from probabilistic analysis imply that rainfall is a relatively inferior factor affecting slope stability.This study aims to provide preliminary guidance on risk management and early warning in the TGR area.
基金supported by to the National Key Research and Development Program of China(No.2018YFC1505401)。
文摘This study focuses on the deformation characteristics of Kadui-2 Landslide by the influence of reservoir filling-drawdown and precipitation.A three-year monitoring project was implemented in order to observe the short/long-term deformation.The slide mass experienced consistent deformation with a maximum cumulative displacement of 331.34 cm.Based on the recorded data of reservoir water level and precipitation during this period,a two-dimensional(2-D)finite element model using Geostudio software was set up for deformation simulation under different conditions to understand the real influence of these triggering factors on landslide.The numerical simulation results are in consistent with monitoring field data.Both numerical simulation and field monitoring results exhibit that the maximum deformation occurred at the foreside of slumping mass.The slip surface shows significant creep characteristics decreasing as long-term shear strength reducing gradually.Reservoir water level fluctuation is the primary triggering factor to reactivate the landslide mass and has a negative correlation with deformation rate.Displacement rate increases with the reservoir drawdown and decreases with impoundment rise.Compared with reservoir filling-drawdown operation,rainfall has no significant effect on the slide motion of landslide due to limited penetration from the ground surface.
