Experimental investigation into the physical properties of mixed soil within sliding zones and landslide slip zone evolution process analysis

Abstract The formation of slip zone is a key process for the landslide disasters occurrence. This study aims to investigate the physical properties of a complex multicomponent sliding zone soil within a typical large landslide, shedding light on the mechanisms behind sliding zone formation. Various physical testing methods were employed to analyze the mixed sliding zone soil, which is comprised of several components. The primary constituents of the sliding zone soil, including fully weathered tuff soil and silty clay, were combined in different proportions using materials sourced from a representative landslide site. Analyses methods encompassed liquid-plastic limit tests, unconfined compressive strength tests, direct shear tests, and water retention capacity assessments. Experimental findings underscore the substantial alteration of physical properties in the sliding zone soil due to the intermixing of multiple soil components during the slope's sliding zone formation. This alteration is chiefly characterized by a reduction in shear strength and water retention capacity. Consequently, mixed sliding zone soil is more susceptible to waterlogging and saturation phenomena. Based on the experimental data, the formation process of a typical landslide slip zone was revealed.