Experimental study on deformation and failure of a mining slope under the action of rainfall

On August 28, 2017, the collapse of a mining slope in Pusa Village, Guizhou Province, China, released approximately 8,600 m3 of earth and rock, killing 35 people. This study, analyzes the deformation damage mechanism and progress of a simulated rainfall-induced mining slope collapse. The results show that the stress at the monitoring points changes under the action of mining, with the stress concentrated at the upper monitoring points of the mined-out area. A number of mining fractures are generated after the mining stress in the model is adjusted; these fractures were interconnected and gradually continued to the top of the slope as a consequence of rainwater infiltration. The simulation results demonstrate how, with continued mining of the coal seam and rainfall, the displacement value and range gradually increase, with maximum displacement occurring at the top of the mined-out area. The damage mechanism can be described as follows: subsurface mining disturbs the rock mass generating fractures; under rainfall, the fractures extend, further decreasing the rock strength and leading to a rise in water pressure inside the slope body; and, ultimately, deformation of the slope surface leads to collapse.