Physical model experiments of gently inclined shallow accumulation-layer slopes failure sliding along the soil–bedrock interface triggered by rainfall

A heavy rainstorm in Nanjiang County triggered many accumulation-layer landslides that slid along the soil‒bedrock interface on September 16, 2011. A series of physical model experiments were conducted to study the influence of factors such as the rainfall intensity and sliding bed gradients on the deformation and failure of the accumulation-layer slope. The entire process of slope sliding instability caused by heavy rainfall in the red layer area was reproduced, and the characteristic parameters of slope deformation and fracture were obtained, elucidating the sliding instability mechanisms of the slope. The experimental results revealed that the rainfall intensity was higher and that the rainwater tended to converge to the soil–bedrock interface, which was more prone to destabilization damage. When the accumulation-layer slopes of the sliding bed were gentler, the slopes did not easily slide, and the pore-water pressure at the soil‒bedrock interface was greater during sliding. The failure mode of the shallow accumulation slope was a slip crack that slid along the soil‒bedrock interface.The entire process of sliding instability of gently inclined shallow accumulation-layer slope induced by heavy rainfall along the soil–bedrock interface was simulated through physical model experiments, and the sliding instability mechanism of the slope was elucidated.The results of this study are of great significance for the early warning of such landslide disasters and the improvement of landslide disaster prevention and control capabilities.