Deformation Characteristics And Stability Evaluation Of Toppling Rockmass Under The Effect Of Reservoir Water

Duonuo hydropower station is located in jiuzhaigou county,sichuan province baishuijiang upstream tributaries of the river basin level,and the D area is located in the right bank of the downstream side,which is oblique transverse slope as a whole.After reservoir impoundment,the monitoring data show that surface deformation range of region D is much bigger,and the deformation continues to increase,which gradually formed a faulted slab close to the maximum width of half a meter at gate shaft near 2324 m elevation secondary concrete interface.More north hydropower station signs of toppling deformation on the right bank of reservoir area was found after field investigation in the study area,so its stability analysis and evaluation should be made.Combining with previous research results,through field site investigation and monitoring data analysis,the basic structure characteristics of the toppling of body in the studied area,the factors influencing deformation,deformation mechanism is analyzed,and through the qualitative and quantitative methods to make analysis and evaluation on the stability of the study area,the understanding and conclusion was made as followed:(1)Through data collection and the study area geology background investigation,which is understandable that the toppling rock mass in the study area mainly consist of thick layer of feldspar quartz sandstone with thin layer slate,and on both sides by a gully,forming three empty terrain.Through field geological survey,the surface deformation phenomena is found out,whihc determines D area toppling rock mass on the right bank of Duonuo hydropower station reservoir area distribution characteristics and scope;And on the basis of drilling exploration,from the stereo configuration determines the boundary and the partition characteristics of toppling rock mass.(2)Based on the results of field surface geology survey and factors affecting the deformation of the toppling rock mass,after the comprehensive investigation and analysis,,thought the toppling of deformation in the study area is mainly divided into three stages: unloading ripping,bending toppling,strongly curved,covered rock mass collapse.(3)D district toppling rock mass in the study area is affected by the water lifting effect for a long time,the slope rock mass is often in a state of "dry-wet alternate".In order to explore the effect of reservoir water on the influence law of slope rock mass,and provide physical and mechanical parameters for slope stability evaluation,designs the dry-wet circulation under the action of conventional triaxial and uniaxial tests.Through the analysis,the study found rational water quality weakening in geotechnical engineering is one of the important factors that toppling rock mass deformation become gradually aggravate in the study area.On this basis,using the rigid body limit equilibrium analysis of slope stability calculation in the studied area,the slope stability coefficient ? analysis and evaluation under different working conditions is obtained.(4)The monitoring system of region D toppling rock mass is designed on the basisof the deformation mechanism analysis and stability evaluation,and two monitoring section(8-8',9-9')on D district toppling rock mass were arranged,the monitoring results shows that the precipitation during storage of slope deformation,deformation depth range and direction,and deformation survey of surface and underground,mechanism analysis and stability evaluation results.