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.