Seepage-stress coupling analysis of Dayeping landslide in Linxihe Hydropower Station

The seepage-stress coupled interaction of weak intercalated layer is the key factor affecting landslide stability. In order to estimate the integral stability of Dayeping landslide with weak intercalated layer, based on Biot consolidation differential equation, according to Goodman element form and introduced the interpenetration check idea of Desai element, 2D four nodes coupled thin-layer element is established by virtual displacement principle. An elastic-viscoplastic constitutive model is given to simulate the creep of landslide; and a corresponding finite element program is developed; then the program is verified by in-situ pore pressure testing data. At the same time, by using nonlinear FEM the seepage-stress coupling analyses of Dayeping landslide are carried out under normal water level and water level falling suddenly. The results indicate that the landslide is stable under normal water level, but under water level falling suddenly, landslide stability becomes worse because water level falling suddenly make the pore pressure, displacement, shear stress, plastic zone increase rapidly in middle-front part, and this may result in landslide middle-front part slipping along weak intercalated layer. In the end, rigid limit equilibrium method is used to verify coupled results; and the two conclusions are coincident. The analyses provide important theoretical basis for the comprehensive evaluation of Linxihe Hydropower Station construction feasibility, and the method establishing coupled element for analyzing weak intercalated layer provides helpful references for dealing with the stability of other landslides with weak intercalated layer.