关键词: 瓦斯抽采, 耦合模型, 渗透性, 吸附应变

Abstract: In order to reveal the influence of coal deformation on the seepage law of gas drainage, a study on the gas-solid coupling law of coal seam gas drainage was carried out. Considering the changes in coal adsorption deformation, pore pressure and permeability, and assuming that the gas migrates by Darcy flow, a gas-solid coupling equation of coal seam gas seepage and coal deformation with effective stress and adsorption strain as the coupling medium was established. Taking the field conditions as the background, numerical analysis was carried out on the displacement, adsorption strain and gas seepage characteristics of the drainage coal seam, and the coupling effect of gas pressure, permeability and gas drainage volume was compared and analyzed. The results show that the displacement of the coal seam around the borehole increases after drainage, the coal body shrinks and deforms due to gas desorption, and the closer it is to the drainage hole, the greater the strain; The gas pressure drop gradient in the coal seam at the initial stage of drainage is larger; After drainage, the coal seam permeability shows an increasing trend, the closer it is to the borehole, the greater the increase. When considering the coupling effect, the overall trend remains the same but the increase decreases; the gas drainage volume in the initial borehole is larger but the decrease is faster, and then tends to stable. Compared with the actual drainage volume, it is found that the model calculation results are more consistent with the actual drainage data.