Experimental study on granite-weathered crust landslides with different residual layer thicknesses under heavy rainfall

Abstract. Landslides are frequent in granite areas during rainfall. The hydrological response and deformation damage mechanisms of granite-weathered crust slopes were investigated by physical model tests. The variability of the material with respect to the thickness of the residual layer was taken into account. The results show that the three types of slopes exhibit distinct disaster mechanisms. For the E1 slope (10 cm residual layer), the residual layer was rapidly saturated, and seepage was formed. The residual soil was susceptible to severe suffosion, and an overall flow-slip failure occurred with no obvious sliding surface. For the E2 slope (20 cm residual layer), rainfall infiltrated the soil–rock interface, forming a temporary water table at this location. The slope tended to slide along the soil–rock interface at the foot of the slope under the traction and drag of water flow. For the E3 slope (30 cm residual layer), rainfall failed to infiltrate the interface, and no seepage was observed within the slope. The slope gradually slides within the residual layer under hydrostatic pressure and self-weight, with a circular arc sliding surface. This study fills the gap in granite-weathered crust landslides with different residual layer thicknesses and has certain theoretical significance.