Characterization of soil composition and calculation of genetic mechanism in the landslide zone of Liujiabao landslide in Three Gorges reservoir area

The Three Gorges Reservoir Area is a hotspot for landslide disasters, with many landslide development patterns and influencing factors remaining unclear.The slip zone soil, a weak interlayer between the sliding mass and the bedrock, has inherently low strength, which is a critical factor in landslide occurrence.Water is one of the most active elements reducing the shear strength during the formation of the slip zone.Given the particularity of reservoir bank water-related landslides, the mineral composition and geochemical characteristics of the slip zone and its surrounding rocks and soils exhibit significant variations across different geological periods and environments.These changes reveal the mechanisms and extent of water-rock interactions, further clarifying the fundamental reasons for the reduction in shear strength of the slip zone.The results show that in the Liujiaobao landslide in Quchi Township, Wushan County, Chongqing, within the Three Gorges Reservoir area, the composition of minerals and the content of major chemical elements in the slip zone soil and its surrounding rocks and soils indicate that the slip zone and surrounding rocks and soils form the material basis for the slip zone.During its formation, the groundwater in the slip zone is closely connected with external hydraulic forces, continuously influenced by groundwater, leading to changes in the physical properties of the rock and soil mass.This is accompanied by the hydrolytic mudification of marl debris, dissolution of calcite, and interconversion among clay minerals, which are the main reasons for the attenuation of the shear strength of the slip zone soil.