During the multi-seam mining process in Southwest China, the overlying strata are characterized by a wide influence range, complex deformation mechanisms, and severe damage, which exacerbate subsidence and deformation of mine slopes, trigger geological disasters, and lead to severe casualties and economic losses. To reveal the deformation and failure mechanisms of slopes under the influence of multi-seam mining, this study integrated the typical engineering geological conditions, deformation characteristics, and subsurface mining conditions of mine disasters in the mountainous regions of Southwest China. A simplified conceptual model was established, and the base friction tests were conducted. Using digital photogrammetric deformation measurement (DPDM) technology, the deformation evolution of mine slopes under different coal seam dip angles and varying mining layers was explored. The results showed that repeated mining activated disturbance in the overlying strata, promoted fissure network development and connectivity, and intensified slope subsidence. As the strata's dip angle increased, the overlying strata's deformation range expanded slowly with a stronger lag effect. The failure mode of the slope remains predominantly toppling failure. The deformation evolution process of gently inclined slopes under repeated mining can be divided into surface modification, bending-cracking, and plastic flow-cracking. The spatial distribution of stress was categorized into tensile deformation zones, tensile-shear deformation zones, shoving deformation zones, and collapse deformation zones. The research findings provided theoretical and technical support for understanding the mechanism of slope deformation and failure, as well as for monitoring and early warning of multi-seam mining.
 

multi-seam mining,dip angle of rock stratum,failure mechanisms,base friction tests,failure mode