Mechanism of and Prevention Technology for Water Inrush from Coal Seam Floor under Complex Structural Conditions—A Case Study of the Chensilou Mine

Abstract

Based on the complex hydrogeological conditions of the Chensilou mine, numerical simulations and field validation methods were used to study the mechanism of water inrush from the floor of the coal seam, which has faults and cracks, as well as the regional advanced grouting reinforcement technology during the coal mining process. The evolution laws of the roof stress field, displacement field, crack field, and plastic area are revealed at different mining distances. The coupling mechanism of floor water inrush channel formation under complex conditions is analyzed. Advanced grout filling reinforcement technology in the ground area is proposed, the slurry diffusion law of different grouting layers under different grouting pressures is revealed, and the grouting effect is evaluated, which provides a research basis for selecting a reasonable grouting pressure. Finally, the application of regional advanced grouting reinforcement technology was carried out at the site, and the grouting reconstruction effect was verified by the transient electromagnetic and three-dimensional DC resistivity method. The results show that the apparent resistivity of the floor after the grouting reinforcement is high, and the water yield of the verification borehole is less than 10 m3/h. The area where the three-dimensional direct current resistivity is less than 12 Ω·m only appears in the lower part of the middle of the working face, and there is no water in the verification borehole. Through our underground supplementary treatment and verification process, the initial water inflow meets the requirements of being less than 10 m3/h. It indicates that the ground regional advanced treatment project achieved significant results. The results of our research can also provide references for water hazard control in similar mines.