Abstract: There are close relationships between the dynamic changes of seepage field in slope and the failures of reservoir slopes. The traditional analysis methodology based on saturated seepage law isn’t able to describe the dynamic changes law of pore water pressure in slope while reservoir water lever fluctuating. Based on the theory of unsaturated and transient seepage, and the representative hydraulic parameters of 3 typical porous media selected, the finite element analysis of the seepage field is conducted with respect to the ideal layered slope containing relative impermeable intercalated bed. The distributions of pore water pressure and free surface in slope are obtained. Moreover, the diachronic changes of soil matric suction and volumetric water content corresponding to water lever fluctuating are obtained. The analysis reveals that the soil saturated hydraulic conductivity, characteristic curve of soil-water, and the structural feature of slope determine the pore water pressure and free surface distributions together. The modeling results can provide evidences for the evaluating of slope stability and the design of water draining and enforcement measurement for such type slope.

Key words: reservoir slope, unsaturated unsteady seepage, finite element numerical analysis