The Study Of Slope Stability Of The Right Lower Dam Of Jinsha River Batang Hydropower Station

This thesis studies the slope of the right bank dam abutment of Jinsha river Batang hydropower station.Based on the study of the area and dam site engineering geological condition,this thesis main researches the geological characteristics of the right bank dam abutment slope engineering,and divides the slope rock mass weathering unloading,and analyzes the influence of the Xiongsong-Suwalong rupture for the right bank dam abutment slope rock mass structure,rock mass quality,and slope deformation and failure model.In the end,different methods for stability analysis are adopted to evaluate the stability of the right bank dam abutment slope.The conclusions of this thesis are obtained as follows:(1)Combining with the field investigation,on the basis of the qualitative classification of the rock mass weathering unloading,the wave velocity ratio is used to quantitatively divide the slope rock mass weathering band.We obtain that the strong weathering depth of the right bank dam abutment slope rock mass is 0~36m,and the strong unloading depth is 0~58m,and the weak weathering depth is 36~158m,in which the Xiongsong-Suwalong rupture is 108~158m,and the weak unloading growth depth is 58~155m of the the cave class.(2)This thesis analyzes the development characteristics of each class structural surface of the right bank dam abutment slope.Under the influence of Xiongsong-Suwalong breakage,the superficial slope rock mass is broken,and the rock mass structure is given priority to the cataclastic structure,mosaic structure and block structure.(3)Affected by the Xiongsong-Suwalong rupture fracture,the rock on both sides of the fault zone and the fault zone has obvious changes: from the table to adit slope 55 m deep,it is mainly ? kind of rock mass;55 ~ 80 m adit section,it is mainly ? kind of rock mass;80 ~ 108 m adit,it is mainly ? kind of rock mass;108 ~ 158 m adit,it is mainly ? ~ ? kind of rock mass;158 ~ 181 m adit,it is mainly ? ~ ? rock mass;181 ~ 200 m adit section of rock mass is given priority to with ?.(4)The basic forms of the right bank slope natural slope deformation and failure are main the slippage-rip type,the inbreak slump type,the unloading-splitting type and the wedge failure type.(5)By using the finite element method,the overall stability of the right bank abutment slope is analyzed.On the basis of this analysis,searched the rock block that may combinated,using stereographic projectionand 3-D geological model.The limit equilibrium method is used for stability analysis and evaluation of the large body which is formed by Xiongsong-Suwalong fracture and the weak structural plane of the flat slope;Using the theory of block on the slope may be composed of small block is analyzed,it shows that there exist small unstable block rock mass in local area.At the same time,the sensitivity of the angle of internal friction and horizontal earthquake acceleration of the part composite block is analyzed.It is concluded that the block stability of the slope increases with the increase of the structure of internal friction angle and decreases with the increase of the horizontal seismic acceleration.(6)By using the finite difference method,3-D numerical simulation of the overall stability of the right bank abutment slope is analyzed.The simulated working condition contains 2 step,one step is natural condition and after excavation codition.The calculation results show that after the slope excavation,unloading rebounding occurs in the place of excavation part,and rebounding orientation is to the air face.Most plastic zone and displacement part are mainly along the excavation surface and the direction of faults or intersection part of faults.Affected by Xiongsong-Suwalong fault band,the displacement of the slope near the starting position of the excavation is the largest(up to 0.32063m),and the slope deformation and failure may locally present without the dealing condition of the supporting measure.