Research on the Damage Law and Prevention Measures of the Substrate under the Action of Water and Rock

Abstract

The potential of sudden water accidents induced by damage to the bottom slab that forms a water channel due to the action of karst water calls for research on the damage law of coal seam floors under the coupling effect of mining and karst water. In this study, the coupling situation of karst water and floor rock was analyzed based on the theory of rock mechanics and fracture mechanics, combined with the actual geological conditions of a coal seam floor. The law of water-rock coupling was investigated using theoretical analysis and mechanical tests. Results indicate that the strength of the bottom slab rock decreased significantly when the karst pore water was coupled with the bottom slab rock. A three-dimensional numerical model was established using FLAC3D software to simulate the mining situation of the working face under different water pressures. By analyzing the stress change, water pressure change, and plastic zone damage of the bottom slab, it was discovered that the damage effect of karst water pressure on the bottom slab continues to increase when the water pressure is greater than 3 MPa. The impact caused by water pressure greater than 6 MPa occurs gradually. Analysis of measures to prevent and control sudden water on the bottom slab indicates that grouting reinforcement can effectively prevent and control the bottom slab karst sudden water problem.