Gas migration law of protective layer mining under multifield coupling conditions

In order to study the gas flow, gas stress, and coal spatial migration laws under the mining conditions of the protective layer in Dashucun Mine, a multi field coupled mathematical model for protective layer mining was established based on previous research, and boundary conditions were established. Using FLAC3D simulation software, the stress field characteristics, displacement field characteristics, and gas migration laws of the overlying rock layers of the protective layer were systematically studied. The results show that as the protective layer working face advances, the overlying rock strata in the goaf collapse and detach, and the stress-affected area gradually penetrates, playing a role in relieving pressure on the protected coal seam above, and the supporting pressure of the working face decreases; The transfer speed of gas from the protective layer to the inner side is increasing, and the gas diffusion at the top and bottom of the roadway is rapid in space. The most obvious effect is at a depth of 300 m, which is conducive to seepage but also prone to gas accumulation.