关键词: 远距离煤层群, 下保护层, 数值模拟, 卸压

Abstract: On the condition of coal seam groups mining with far distance, the research on pressure-relief study of overlying coal rock body using long distance lower protective seam mining applied the discrete element numerical analysis technology to monitor and analysis the coal seam pressure-relief effect. The NO.10 mine of PingDingShan TianAn Coal Co.Ltd was the background of the project. At the same time, the roadway deformation in the process of the protected coal seam roof alleys and coal pillar mining 248m apart from lower protective seam were calculated and analyzed. The result showed that, the distance between the mining face of the lower protective seam and upper rock roadway was 248 m, but the effect of mining was still significant, leading to the large deformation and subsidence of the alleys of overburden rock over a long distance and loss of function. This was consistent with the field observed situation. It showed that numerical simulation test and field test results were identical, and verified the reliability of the numerical experiments for pressure-relief effect; after the lower protective seam mining, the vertical stress of the protective seam 180m apart was reduced by 20%, the pressure-relief protection angle was about 80° and the inflation rate of pressure-relief expansion region was 2.25% ~ 2.25%. This showed that, mining protective coal seam beforehand had a obvious pressure-relief effect of overlying coal. So overlying coal can be protected.