Experimental study on the failure mechanism of interbedded anti-dip rock slope induced by underground mining

To investigate the fracture propagation characteristics and failure mechanism of anti-dip rock slope induced by underground mining, the Jiguanling landslide in Wulong, Chongqing, China is taken as the prototype, and physical model test is utilized to study the fracture evolution process, deformation characteristics and failure mechanism of anti-dip rock slope. In this study, the digital image correlation (DIC) technique and pressure acquisition system are combined to analyze the displacement and stress field of rock slope during underground mining stages. The results show that the anti-dip rock slope experiences four stages during underground coal mining: tensile fracture propagation in upper toppling zone, shallow damage in the lower shear zone, coal seam roof caving, failure of the whole slope. There is a phenomenon of local tensile and compressive stress conversion in upper toppling zone after roof caving. The appearance of coal seam roof caving increases the compressive area and pressure of the shear zone, leading to the failure of the shear blocks at the front edge, and ultimately causing failure of the whole slope. Mining with retained coal pillar before shallow failure in the shear zone can effectively block the impact of lower mining on the upper toppling zone, achieve a 16% contraction in toppling zone, and improve the stability of the slope. The failure mode of slope can be summarized as shear–slip–toppling collapse failure. This paper improves the understanding on the failure mechanism of anti-dip rock slope caused by underground mining.