Deformation Mechanism Analysis And Stability Estimation Of Qishuwan Unstable Slope

After the earthquake of"5.12"happened in Wenchuan, there are over 1700 shattering mountain which is the splitting, but not "slide", and loosing, but not move. Those make an enormous harm to the people's lives and properties security who lived in disaster area of earthquake. Most of the shattering mountain distribute in county of Qingchuan which is also the severity disaster area.This article use the shattering mountain of Qishuwan unstable slope in Qingchuan county, Sichuan province as the object of study, and follow the basic techniques line of field research, establish the model of concept, mechanism of deformation and destroy and validate simulations, evaluation of the stability and the suggest of control measures, based on a great deal of geological survey of unstable slope in field, we studied geologic conditions, structural features of the slope body and the rock and soil and the deformation features of the slope comprehensively. On this basis, analyze the mechanism of the development of the geological evolution process of the slope, particularly the evidence of deformation and failure appeared in the body of slope after the earthquake of"5.12"in Wenchuan. Establish the model of concept of mechanism of deformation and failure. After that used the program of FLAC3D make a numerical simulation analysis to the model of concept, verified the correctness of the model of concept and the accuracy of the parameter values. On the basis of lucubrate the mechanism of deformation and failure, using limit equilibrium method make analysis and evaluation to the stability of the plasmodium in different parts of the slope and in different working conditions, and calculate the slide force of the plasmodium in different parts of the slope, base on this bring forward the relevant control measures to the plasmodium in different parts of the slope. Gained the following major research result:(1) Through the analysis of geological information and the survey results in field, Qishuwan unstable slope in the earthquake of"5.12"in Wenchuan has three major areas which have clear evidence of deformations, named unstable slope body of areaâ… , areaâ…¡and areaâ…¢. Among them, areaâ… and areaâ…¢is formed by the deformation in the effect of earthquake of the collapse and accumulate of the slope which is made of detritus and soil, areaâ…¡is caused by the resurrection of the old deposit of the slope.(2) Analyzing accord to the deformation feature and effect factor of deformation of the slope after the earthquake, using the analysis method of the geological origins mechanism analyze the model of deformation and failure of the slope, and then on this basis of adopt the program of FLAC3D which has the function of analysis failure by pull and shear make a numerical analysis to the mechanisms of deformation of Qishuwan unstable slope in the effect of earthquake. the analysis showed that:â‘ The factor of cause deformation and failure of the slope to happen is the powerful horizontal axis inertial forces provides by earthquake.â‘¡The deformation mechanisms of the slope in the effect of earthquake behaved as there are clear failure by pull in the back of the slope, some failure by shear in the front of the slope, but not formed cut slide surface which is run-through yet, the model of deformation and failure can reduce to rip by shake in the back, deformation by shear in the bottom.â‘¢The old deposit of the coast did not appear clear overall deformation and failure in the earthquake., only a little scale resurrection in some part where is steep, this related to the nonage potential energy of the slope is dissipation plentifully and the gradient of the old deposit of the slope is smooth.(3) Use the method of limit equilibrium analyzes and evaluates the stability of the slope in the condition of nature, nature and rainstorm, nature and earthquake. The result shows: the possibility of unstable slope of areaâ… along the potential major slide surface occur deformation and failure is small. The rock and soil on the up of the potential sub slide surface is under stable in the condition of rainstorm and earthquake, its emergency capacity is low. It is likely to unstable in conditions of continuance rainstorm. Unstable slope of areaâ…¡is stable in the condition of nature, but unstable in the condition of rainstorm and earthquake. The stability of unstable slope of areaâ…¢in the condition of nature is good, under stable and unstable in the condition of rainstorm and earthquake, it is likely to deformation and failure in the condition of continuance rainstorm.