Abstract: In this paper, the two-dimensional finite element model of unsaturated double-layer soil slope is established based on the seepage theory and the strength theory of unsaturated soil. The distribution of pore water pressure field and the slop stability coefficient under the condition of heavy rainfalls are analyzed. The results show that the distribution of pore water pressure field of unsaturated soil slope is related to the duration of rainfall. In the early stage of rainfall, the pore water pressure at the toe of the slope increases. With the rainfall time increase, the positive pore water pressure on surface gradually expands and penetrates, and the range of negative pore water pressure gradually reduces. The stability coefficient of the unsaturated soil double-layer soil slope decreases linearly with the increase of rainfall time.

Key words: Heavy Rainfall, Double Soil Slope, Unsaturated Soil, Slope Stability Analysis