In this study, strength softening models are developed for exploring rainfall-induced landslide mechanism based on Mohr-Coulombstrength theory with both saturation degree and temporal evolution into consideration. According tothe ratio of two time scales available, the model can be classified into three categories, i.e., instant softeningmodel, delay softeningmodel, and couplingsoftening model.Corresponding evolution functions are specified to represent these kinds of softening processes andthen applied to simulate landslide of homogeneous slopes triggered by rainfall, therefrom, usefulconclusions can be drawn in the end.
