基于摩尔-库伦准则以孔代巷上隅角瓦斯治理研究

Research on Gas Control in Upper Corner of Roadway Replace Lane with Hole Based on Mohr-Coulomb Criterion

为解决工作面U型通风上隅角瓦斯积聚问题,提出了以孔代巷的抽采工艺,根据摩尔-库伦破坏准则和采空区覆岩裂隙发育理论,分析了成孔过程孔壁变形和孔隙结构变化规律,得到了有效应力作用下孔壁煤体变形量;同时根据岩石力学公式,计算得到了高位钻孔的合理抽采层位。通过对比以孔代巷和普通钻孔的抽采数据表明:在钻孔终孔高度高于顶板43 m,负压20 kPa的条件下,以孔代巷抽采工艺下的单孔瓦斯抽采浓度达到58.92%,较普通钻孔提高了3.5倍;单孔瓦斯纯量达到0.045^(3)/min,相比普通抽放钻孔增加了8.5倍;采空区瓦斯涌出量降低到1.32^(3)/min,减少了29.03%,上隅角瓦斯浓度为0.14^(3)/min,降低了67.44%;采空区瓦斯抽采时间为45 d,比联络巷密封插管抽采减少了35 d,该研究对采空区上隅角瓦斯抽采提供了理论依据。

In order to solve the problem of gas accumulation in the upper corner of the U-shaped ventilation of the working face,a drainage process with a hole instead of a lane was proposed.According to the Mohr-Coulomb failure criterion and the theory of overburden crack development in the mined-out area,the hole wall deformation and the pore structure changes the law,and the deformation of the hole wall coal body under the effective stress is obtained.At the same time,according to the rock mechanics formula,the reasonable drainage layer of the high-level drilling is calculated.Comparing the extraction data of replacing lanes with holes,and ordinary drilling shows that under the condition that the final hole height of the borehole is higher than the roof 43 m and the negative pressure is 20 kPa,the single-hole gas extraction concentration under the replacing lanes with holes.Extraction process reaches 58.92%,an increase of 3.5 times compared with ordinary boreholes;the pure gas drainage volume reaches 0.045^(3)/min,an increase of 8.5 times compared with ordinary boreholes;the gas emission in mined-out areas is reduced to 1.32^(3)/min,a decrease of 29.03%.The gas concentration in the upper corner is 0.14^(3)/min,a reduction of 67.44%;the gas drainage time in the mined-out area is 45 days,which is 35 days less than that of the sealed cannula in the joint roadway.Gas drainage provides a theoretical basis.