关键词: 近距离煤层群, 高瓦斯煤层群, 保护层开采, 数值模拟, 应力分布, 卸压瓦斯抽采

Abstract: In order to solve the problem of gas overrun in the upper corner or return air flow caused by a large amount of gas flowing into the goaf of the working face due to pressure relief after the mining of the upper protective layer under the condition of short-range high gas coal seam group, the 03X00 working face of Dongyu mine in Xishan coalfield of Xifenliu mining area is taken as the research object, The stress distribution of the protected layer after the mining of the upper protective layer is analyzed by using the method of theoretical calculation and numerical simulation, and the law of pressure relief gas migration is obtained, so as to determine the vas treatment technical scheme of "one working face and three lanes" arrangement of the working face and pre drainage of the overlying coal seam + pressure relief drainage of the underlying coal seam. The field results show that after the mining of 03X00 working face, the No. 2 coal seam is completely within the pressure relief range, the pressure relief rate of the protected No. 2 coal seam reaches 92%, the gas content and gas pressure of the coal seam decrease significantly, the reduction rate reaches more than 60%, the pressure relief gas extraction concentration increases by 60%, the pure quantity increases by nearly one time, and the maximum gas concentration of the return air flow of the track chute and the bottom drainage roadway is 0.3%, The maximum gas concentration in the upper corner is 0.4%, which avoids gas overrun, ensures mine safety production, and provides scientific support for coordinated mining of coal and gas.