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
The deformation and failure of mining slopes in layered rocks predominantly result from shear landslides.However,the instability process of the Pusa rock avalanche in Guizhou,China,revealed a unique damage phenomenon:...The deformation and failure of mining slopes in layered rocks predominantly result from shear landslides.However,the instability process of the Pusa rock avalanche in Guizhou,China,revealed a unique damage phenomenon:prominent breaking and toppling of rock blocks occurred in the central section of the mountain,with a lack of commonly observed shear landslide features.This paper aims to investigate the underlying reasons behind this distinctive damage pattern.The study employs various methods including geological survey,UAV aerial survey,physical simulation,and discrete element numerical simulation.The findings indicate that the geological conditions,characterized by a hard upper layer and a soft lower layer along with underground mining activities,play a significant role in triggering the landslide.Furthermore,the presence of a columnar structured rock mass emerges as the primary factor influencing the instability of the Pusa rock avalanche.To elucidate the mining failure mechanism of the rock mass with vertical joints,we propose a"subsidence-buckling"failure model.Following the subsidence and collapse of the roof rock mass in the goaf,the columnar rock mass in the upper and middle portions of the slope undergoes deflection and deformation,forming a three-hinged arch structure.This structural configuration converts the pressure exerted by the overlying rock mass into both vertical pressure and lateral thrust.Under the influence of external loads,the slope experiences buckling failure,ultimately leading to instability upon fragmentation.By shedding light on these findings,this study contributes to a better understanding of the spatiotemporal evolution of mining slope fractures and their impact on slope stability.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funded by the State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Independent Research Project(SKLGP2022Z001)National Natural Science Foundation of China(Grant No.41877273)+3 种基金Science and Technology Plan Project of Sichuan Province(Grant No.2021YJ0053)Sichuan Natural Science Foundation(Grant No.2022NSFSC1176)Innovative Research Groups of the National Natural Science Foundation of China(Grant No.41521002)POWERCHINA Science and technology project(Grant No.DJ-ZDXM-2020-03)。
文摘The deformation and failure of mining slopes in layered rocks predominantly result from shear landslides.However,the instability process of the Pusa rock avalanche in Guizhou,China,revealed a unique damage phenomenon:prominent breaking and toppling of rock blocks occurred in the central section of the mountain,with a lack of commonly observed shear landslide features.This paper aims to investigate the underlying reasons behind this distinctive damage pattern.The study employs various methods including geological survey,UAV aerial survey,physical simulation,and discrete element numerical simulation.The findings indicate that the geological conditions,characterized by a hard upper layer and a soft lower layer along with underground mining activities,play a significant role in triggering the landslide.Furthermore,the presence of a columnar structured rock mass emerges as the primary factor influencing the instability of the Pusa rock avalanche.To elucidate the mining failure mechanism of the rock mass with vertical joints,we propose a"subsidence-buckling"failure model.Following the subsidence and collapse of the roof rock mass in the goaf,the columnar rock mass in the upper and middle portions of the slope undergoes deflection and deformation,forming a three-hinged arch structure.This structural configuration converts the pressure exerted by the overlying rock mass into both vertical pressure and lateral thrust.Under the influence of external loads,the slope experiences buckling failure,ultimately leading to instability upon fragmentation.By shedding light on these findings,this study contributes to a better understanding of the spatiotemporal evolution of mining slope fractures and their impact on slope stability.
