Shallow Landslide Model of Granite Residual Soil Considering Shearing Dilation Effect and Seepage Force

The granite residual soil slopes in southeast Guangxi, China, occur failures and cause frequent landslides under rainfall conditions. Shallow landslides are the main failure mode. Shearing dilation effect and groundwater seepage both exist within the landslide movement. The movement characteristic is the scientific basis of landslide prevention and warning. In this study, a shallow landslide model of granite residual soil is established to reflect the coexistence of shearing dilation effect and groundwater seepage. The results include three aspects. (1) Groundwater seepage along the slope can lead to the increase of the sliding force, which is not conducive to slope stability. (2) Dilation promotes the formation of negative excess pore pressure, which can counteract the increase in static pore pressure caused by rain infiltration. It has a certain inhibitive effect on landslide motion. Such restriction weakens with the decrease of dilation angle and enhances with the increase of dilation angle. (3) Contraction can prompt the positive excess pore water pressure to increase rapidly to the limit of liquefaction in a short period of time. The research results will provide a theoretical basis for the prevention and warning of rainfall-induced granite residual soil landslide in southeast Guangxi.