Study on the Stability of Soil–Rock Mixture Slopes Based on the Material Point Strength Reduction Method

In this paper, the material point strength reduction method is used to investigate the stability of soil–rock mixture (SRM) slopes and the whole process of large deformation occurring after destabilization. A comparative study with homogeneous soil slopes is conducted. First, a material point slope model with typical shapes, a homogeneous soil slope, and an SRM slope with stones of different sizes distributed inside is established. Next, gravity is linearly added to establish the initial state of the slopes. Then the material strength of the slope is discounted according to the criterion of strength discounting. The material point method (MPM) simulations of the two slopes are carried out separately until the slope’s displacement changes abruptly to determine the slope’s safety factor. The final accumulation form of the slope after the damage is studied. Finally, the deformation characteristics of the two slopes under extreme conditions are explored. The research shows that the stones are beneficial to the slope in maintaining slope stability, and due to the presence of stones, the slope presents different characteristics from the pure soil slope when damage occurs.