Study On Failure Models Of The Bedding Rock Slope At The Right Bank Of The Dam Near Ciha Gorge Hydroelectric Station

Bank slope failure is one of the main engineering geological problems in the construction process of Hydropower Station,Ciha Gorge hydropower station locates in the Ciha gorge junction of Xinghai county and Tongde county in Qinghai province,Ciha gorge belongs to deep valley landforms,Slope is mainly composed of a thin layer ~ each layer of sandstone splint rock,the valley on the left bank is the reverse slope.The right bank is the bedding slope and insequent ~ horizon slope,the right bank of the dam site area near dam is the consequent slope,In near the dam on the right bank of the development of unfavorable geologic bodies have I landslide #,III # landslide and 5# toppling rock mass,correct analysis of these geological bodies failure mode is of great significance on the back of the construction project.Based on the regional geological environment on the slope,the rock mass structure and slope structural characteristics of slope area near the dam on the right bank dam slopes are analyzed in detail,,combined with the feature of deformation and control factors of slope failure,conclude the slope deformation mechanism and failure mode,evaluate the stability of the unfavorable geological body and the influence of the engineering in the research areas.The main conclusion are as follows:(1)Based on detailed field investigation,analysis of the rock mass structure and slope structure,the main rock types in the study area is thin layer ~ interbedded of sandstone splint rock;combination the difference with types,lithology association,deformation characteristics and failure modes of each geological slope,the right bank slope is divided into 6 zones,the drainage slope downstream part is zone?,area is given priority to with horizon slope;zone ? is draining slope portion,is insequent ~ horizon slope;zone ? is the part of ?# landslide,because the Yellow River flows happen here ways,it is bedding slope;zone ? is part of 3# deformable,is insequent slope;district V for Sanchi ditch and 3# body rock slope angle of 42° ~56°,which belongs to the oblique inclined layer shaped slope? area for Sanchi groove upstream part,development in the area have ? # landslide and 5 # toppling body,obliquity of rock layer is 75 ° ~ 82 °,the angle between strata and slope is 18 °~ 28 °,is a steep bedding rock slope(2)Analysis the mechanism of deformation and failure of typical slopes in the study area,? # slope is the mechanism of sliding-bending destruction,? # slope and 5 # toppling bodies are the toppling deformation and failure mechanism.(3)Analyed the slope instability mode influencing factors of the study zone,the study found that their failure mechanism is mainly affected by the influence of terrain conditions,geological structure,airport condition and rock layer angle.(4)The study zone of slope instability mode divided into two major categories of sliding instability and collapse instability,and the sliding instability includes continuous and discontinuous failure surface instability mode.the discrete element method is adopted to study the deformation and failure process of ? # landslide,drawing a steep bedding rock slope is in the long river valley and complex geological evolution process of formation of large area in the process of unloading "stress relief" and the secondary stress field distribution,slope of maximum principal stress and the slope are almost parallel,rock In parallel to the slope of the maximum principal stress as the leading edge of the slope toward the empty direction cantilever bending,as the leading edge of rock mass deforming toward surface deformation,with the back of the rock mass under the action of gravity in the rock formation to slide or rupture,the development of bending to the inner slope,eventually lead to the root fracture of rock mass,form toppling body,after the break surface through,in the influence of rainfall,groundwater,or human activities,toppling body may be sliding,form sliding-toppling landslides.(5)Adopt Rigid Limit Equilibrium Method to study stability in typical unfavorable geological evaluation,and analyzes its influence on the project.