Abstract: The combined transient saturatedunsaturated seepage analysis and slope stability analysis were used study the effect of rainfall event on the stability of a high fill slope. Vadose field of slope is simulated for different rainfall duration conditions. The research results indicate that change of the pore water pressure is mainly concentrated in the location where the water level changes in the process of rainfall. After the rainfall pore water pressure gradually dissipates. Rainfall duration has great effect on the slope stability. With the rainfall duration increases the factor of safety for slope stability decreases. The factor of safety decreases in the process of rainfall, but after rainfall, it increases gradually. The longer the rainfall duration, the longer it takes for the factor of safety to recover.

Key words: Rainfall, Stability of high filling slope, Transient saturatedunsaturated seepage