Numerical analysis of an expansive subgrade slope subjected to rainfall infiltration

A numerical simulation approach fully considered the processes of unsaturated seepage and wetting-induced swelling of unsaturated expansive soil subjected to rainfall infiltration was proposed in this paper. Firstly, a laboratory model test was conducted to verify the accuracy of proposed algorithm. Then, the behavior and failure mode of an expansive subgrade under rainfall conditions was revealed. Finally, a parametric study was conducted to investigate the influences of rainfall intensity, initially matric suction, and slope ratio. The results show that (1) the accuracy and effectiveness of the numerical simulation approach proposed have been well verified. (2) The failure mechanism of an expansive subgrade exhibits a typical shallow slide tendency initiating from the toe of the slope with a decrease in the matric suction and shear strength in the surficial slope. (3) The rainfall intensity and initially matric suction have great influence on the safety factor of expansive subgrade slope.