Unsaturated hydraulic conductivity functions of deposits body are obtained based on Fredlund and Xing methods as well as field tests. According to the generalized geological model

the finite element model of unsaturated seepage analysis is built. Distribution characteristics of pore-water pressure in the slope at different times in the process of reservoir impounding are obtained by numerical simulation. Distribution of transient pore-water pressure and the strength theory of unsaturated soil are applied to the analysis of general limit equilibrium to study the transient stability of the slope while the water level is rising. The results show that the whole stability of the slope is descending with the water level rising. And its local stability coefficient is descended firstly and then ascended with the reservoir water level rising. Owing to the existence of a risk water-level

the lower part of slope body tends to be unstable under certain condition