Deformation and Failure Mechanism of Bedding Slopes Induced by Underground Mining: Case Study from Yanwan Village, Guizhou Province, China

The deformation and instability disasters of mining slopes in the Southwest China mountainous area are frequent. Moreover, geological disasters are characterized by large-scale, strong destructiveness and complex failure modes. To research the collapse in Yanwan Village, Qingzhen City, Guizhou Province, the deformation and failure process of the slope is physically simulated by a bottom friction test. Digital photographic deformation measurement technology is used to monitor the displacement change of the slope. The results show that in addition to the unloading fissures formed by the stream trenching, which affects the stability of the slope, the mining of underground coal seams is the main factor leading to the deformation and failure of the slope. After underground mining, the overlying rock in the goaf first subsides and deforms, so that the stress is readjusted, and tensile stress is concentrated at the top of the slope, and finally a tensile crack is formed. At the same time, the stress above the goaf is distributed in an arched shape, and a horizontal stress concentration zone is formed. The horizontal stress pushes the slope body to move towards the free face, which eventually leads to the collapse of the rock mass at the top of the slope. Therefore, the collapse mechanism of the slope dangerous rock mass under the action of underground mining is cracking-toppling (collapse).