Deformation Mechanism And Risk Prediction Analysis Of Wasizhai Landslide In Li County Of Sichuan Province

Wasizhai landslide is in the northeast of li County, sichuan province. The oldlanslide is made of three landslide. The plane area is0.54km², the depth of slipsurface is10m to30m. The deformation of slope is serious. The slope is divided intothree wards It is easy for partial to revive and transform into debris flow disaster.Once the landslide-debris flows disaster strikes, it will cause significant loss of lifeand property to ridicun people and the State Road317. Therefore, the analysis of therevival mechanism and stability on old landslide contributes to landslide harnessdesign, which will be of significance practice value. While it also can enrich thesystem of complex landslide resurrection mechanism and landslide transformed intodebris flow.In this paper, with the wasizhai old slide basic geological conditions, slope rockmass structure, signs of deformation and fracture as the basis. Study on the oldlandslide formation and evolution mechanisms and the resurrection of the mechanism,using two methods including Morgenstern-Price limiting difference method andFlac^3D finite difference method to analysis and evaluate the stability of the oldlandslide, to predict the risk of landslide transforms into debris flow. In this paper,The main content of the thesis are as follows:（1）The old lanslide is made of three landslide. Analysis the formationmechanism and slope transformation process of three old landslide. With the tectonicactivity, the formation mechanism of the complex landslide and the process of theslope transformation are analysised. When cutting in the valley, the slope deformsdumping-bending, then the fracturing plane transfixed, and Ⅰ#old landslide areformed. Then the rock behind the slope are collapse times during the earthquakes,formed theⅡ#、Ⅲ#old landslide. Which lead to the slump-mass covered the Ⅰ#oldlandslide. Later, slope body slips many times on the effect of loading, water erosion,earthquake, rainfall etc.（2）The whole old landslide has signs of revival. According to slope deformationand failure characteristics, the slope is divided into three wards. The forms ofdeformation and failure are slip-tensile, on the effect of water erosion, earthquake and rainfall, the middle and posterior products tension crack.（3）By Morgenstern-Price limit equilibrium method to analyze the stability ofthe old accumulation landslide body. Old landslide in the natural conditions keep astable state, in the basic steady state in heavy rain conditions, and seismic conditionsin the unstable state; when it is in the strong deformation zone in the naturalconditions, it is in the basic steady state, and in the unstable state during rainstormsand earthquakes.（4）Analysis the feature of the stress fields and displacement field in the cases ofthe natural, heavy rain, earthquakes and front slump s by Flac^3D difference method.The displacement of old landslide in the natural and rainstorms is smaller. The partialdisplacement is larger after loading the level and vertical seismic wave, and thegreater tensile stress area and the plastic deformation zone are appeared. Afterremoving the front-end resurrection body, a whole large deformation appeared,andthe area of tension increases.（5）Analysis the methods of landslide transformation to debris flows, calculatethe maximum velocity and impact if the slump quantity transformed into debris flow,and forecast the disaster.