Abstract:
The presence of boulders alters the stress distribution and rainwater infiltration pathways within granite residual soil slopes under rainfall conditions, consequently exerting a significant influence on slope stability. To gain a deeper understanding of the influence mechanism of boulder position on slope stability, this study conducted physical simulation experiments investigating the effect of boulder position on the stability of granite residual soil slopes under rainfall. The research aims to elucidate the impact of different boulder burial positions on the dynamic instability failure process of slopes and explores the dynamic evolution patterns of soil pore water pressure, earth pressure, and moisture content during rainfall and landslide events. The dynamic instability failure process of the slope was analyzed. The results demonstrate that: (1) The instability failure process of granite residual soil slopes is characterized by progressive slow deformation, rather than a rapid, sudden catastrophic failure; (2) During rainfall, the response curves of soil earth pressure, pore water pressure, and moisture content exhibit a certain degree of hysteresis; (3) The burial position of the boulder critically affects slope stability; specifically, when the boulder is located in the middle section of the slope, the scale and severity of the landslide are greater than when the boulder is situated deeper within the slope or near the surface; (4) Rainfall runoff circumvents the boulder, leading to an increase in the void ratio of the surrounding soil. This creates preferential flow channels conducive to rainwater infiltration, promoting the formation of weak slip surfaces within the slope body, ultimately resulting in slope instability. The position and depth of the boulder are primary factors governing the shape and size of the weak slip surface within the slope. The findings of this study enrich the database concerning instability failure mechanisms of granite residual soil slopes containing boulders, provide scientific guidance and a theoretical basis for early warning analysis of landslides under heavy rainfall conditions, and hold significant importance for enhancing landslide disaster prevention and mitigation capabilities.