Causes, Failure Modes, and Identification Characteristics of Mining-Induced Slope Failures in the Karst Mountains of Southwestern China

Underground mining disturbance alters the initial stress state of rock masses and is an important factor triggering large-scale slope failures in karst mountainous areas. In the karst mountains of southwestern China, dual-layered geological structures composed of carbonate rocks and clastic rocks are widely developed. However, studies integrating lithological combinations, structural discontinuities, and the transmission of mining-induced disturbances into a hierarchical identification framework remain limited. Based on data from 29 representative cases, the deformation and failure characteristics of mining-affected slopes are analyzed, and a hierarchical failure-mode identification framework controlled by dual-layered geological structures is proposed. First, according to stratigraphic structural characteristics, mining-affected slopes are divided into two basic structural types: hard-over-soft and alternating hard–soft strata. These types are further classified according to the development of karst-related structural discontinuities, deformation characteristics of the basal layer, and failure evolution sequence, resulting in nine typical failure modes. Case analyses indicate that lithological combinations and structural discontinuities jointly control slope deformation under underground mining, while deformation of weak basal layers and propagation of karst-related structural discontinuities are key factors governing different failure modes. The identification framework provides a theoretical basis for hazard investigation and identification, mechanism analysis, and risk prevention and control of mining-induced slope failure hazards.