STUDY ON DYNAMIC DEFORMATION MECHANISM OF LANDSLIDE IN DRAWDOWN OF RESERVOIR WATER LEVEL——TAKE BAISHUIHE LANDSLIDE IN THREE GORGES RESERVOIR AREA FOR EXAMPLE

Many landslides in the Three Gorges Reservoir area have large deformation during the drawdown of reservoir water level every year.In order to study the dynamic deformation mechanism,stability and development trend of landslide during drawdown of reservoir water level,this paper takes Baishuihe landslide as an example.Based on the field geological survey,detailed geological exploration,and full use of monitoring data of more than ten years,the deformation characteristics,mechanism,influence factors and stability of landslide are analyzed in detail,and the deformation trend of landslide is predicted.Analysis results show that,during the drawdown of reservoir water level,underground water can not be discharged in time due to the landslide soil permeability is poor.Because decline speed of groundwater is much slower than that of reservoir water,increasing the seepage force in the landslide body apparently,and then further reduces the slope stability.The landslide deformation rate increases with the increasing of decline speed of reservoir water level,and the landslide deformation shows dynamic characteristic of step type.