Mechanism of fracture preferential flow infiltration-induced shallow damage of colluvial landslides

Soil fissures provide infiltration channels for rainfall, and the dominant flow formed along these channels dominates the infiltration process of rainfall, leading to the gradual deterioration of landslide stability and the continuous development of deformation. Taking Xuwa landslide as an example, the geological survey, on-site macroscopic inspection and monitoring data are combined. By analyzing the deformation characteristics of Xuwa landslide, the phenomenon of shallow landslide damage induced by dominant inflow infiltration is elaborated, and numerical simulation is used to analyze the process of dominant inflow infiltration caused by fissures at different depths. Thus, the stability evolution characteristics of shallow landslide under the action of dominant inflow are calculated by the infinite slope model, and the mechanism of shallow damage induced by the dominant flow infiltration is clarified. The study shows that: (1) The fissures improve the permeability and deformation of the slope as well as the promoted fissure development, and the shallow damage is often caused by the continuous evolution of the surface tension fissures generated by landslide deformation. (2) The fissures change the infiltration process of rainwater, part of which infiltrates vertically downward along the surface of the slope, part of which infiltrates along the fissures to the end of the fissures and spreads around, and with the development of fissures, the infiltration of rainfall is dominated by the dominant flow of fissures. (3) The relationship between landslide deformation and fissure development is close. When there is no fissure, the slope is only in an unstable state, characterized by surface erosion damage, while with the evolution of a fissure, the slope is in an unstable state within the depth of fissure influence,