为解决常村煤矿工作面巷道采用"两进两回"设计,煤损失量大,瓦斯抽采效率低问题,利用FLAC3D模拟回采过程中上覆岩层破坏规律,确定了距3号煤层顶板31 m处的K8岩层为关键层,采用UDEC模拟回采过程中上覆岩层裂隙发育及分布规律,得到工作面走向方向裂隙发育区域为距开切眼后方5～48 m;竖直方向裂隙发育区域垂高距煤层顶板21～31 m;开切眼上方采空区断裂带宽度约为40 m,工作面上方断裂带宽度约为48 m;巷帮两侧裂隙发育区域宽度略小于40 m。根据现场对2103工作面邻近S-39工作面裂隙带测试结果,表明上覆岩层裂隙发育带位于煤层顶板36m范围内,与数值模拟结果比较吻合。根据数值模拟与现场测试结果,设计了2103工作面高位瓦斯抽采巷参数:水平层位距回风巷30～45 m,竖直层位距煤层顶板约27m。

A design with two air income and two air returning was applied to the gateways of coal mining face in Changcun Mine, the coal lost was high and the gas drainage efficiency was low.The FLAC3D software was applied to simulate the failure law of the overburden strata during the coal mining process.K8 stratum with a dist ance of 31 m above the roof of No.3 seam was determined as a key stratum.The UDEC software was applied to simulate the crack development and distribution law of t he overburden strata during the coal mining process and the crack development zone along strike direction of the coal mining face was at 548 m beyond the open-off cu t.The vertical crack development zone was at 2131 m vertically above the seam roof.The width of the breaking zone in the goaf above the open-off cut was about 40 m and width of the fractured zone above coal mining face was about 48 m. The width of the crack development zone at the two side of the gateway sidewalls was less than 40 m.According to the measured results of the crack zone in a neighboring coal mining face S-39 of No.2103 coal mining face. The numerical simulation results was con sistent with the test results that overlying strata fissure development zone locates in the 36 m range of roof.According to the results of numerical simulation and test res ults, the parameters of high level gas drainage gateway was designed that the distance between horizontal layer and air return way was 3045 m, the distance between V ertical horizon and coal seam roof was 27 m.