关键词: 数值模拟, 煤层群开采, 应力分布, 裂隙发育, 卸压瓦斯

Abstract: To solve the problem of the channel for the release of pressure relief gas from adjacent lay⁃ ers to the coal seam in Qidong Coal Mine，this study takes the 8235 working face as the research object，and uses UDEC7.0 numerical simulation software to establish a numerical model for coal seam group mining. The stress distribution characteristics of adjacent layers and the dynamic evolution law of fracture field dur⁃ ing the mining process are systematically analyzed. Based on the directional interception drilling and extrac⁃ tion data of the on-site floor，the spatiotemporal evolution mechanism of stress zoning in coal seam group mining was revealed. Research has shown that horizontally，within a range of 30 m in front of the working face，there is a stress rise zone (with a peak value of 60 MPa)，and beyond 30 m，there is an original stress zone (about 35 MPa)；Within 50 m behind the working face is the pressure relief zone (where the stress drops to 1.5 MPa)，and beyond 50 m is the stress recovery zone (where it rises to 25~30 MPa). Vertically，the depth of mining damage gradually expands with the advancement of the working face，and the depth of over⁃ lying rock damage can reach No.9 coal seam floor (vertical depth of about 21 m). The pressure relief range covers the fine sandstone layers in coal seams No.82~No.9. The evolution of the fracture field exhibits a stage characteristic of "opening first and then closing"，and the fracture density in the depressurization zone is sig⁃nificantly correlated with the gas extraction efficiency. The research results have verified the rationality of the directional interception drilling arrangement in the pressure relief zone，providing a theoretical basis for the coordinated mining of coal seams and comprehensive gas control. It has important practical value in re⁃ ducing the risk of coal mine gas outburst and improving the extraction efficiency.

Key words: numerical simulation, coal seam group mining, stress distribution, fracture develop? ment, relieve pressure gas