高瓦斯特厚煤层下分层千米钻孔瓦斯抽采技术

Gas extraction technology of kilometer hole in lower slice of thick and high–gas seams

针对高瓦斯特厚煤层开采上分层时工作面瓦斯频繁超限的问题，依据上分层开采时，下分层在采动应力作用下的破坏程度及卸压瓦斯运移规律，以亭南煤矿205 工作面为试验背景，对下分层千米钻孔瓦斯抽采进行研究。采用理论计算和FLAC3D 数值模拟，确定下分层塑性破坏最大深度约为13 m，千米定向钻孔布置的最佳区域在工作面底板以下6~9 m。通过对不同位置千米钻孔在工作面推进过程中的瓦斯抽采量进行现场监测，结果表明，6~9 m 的千米钻孔抽采效果最为明显，钻场瓦斯抽采量随工作面推进成指数上升，最终增长到68%左右。千米钻孔瓦斯抽采技术实现了对高瓦斯特厚煤层下分层卸压瓦斯长时间、高浓度抽采。

Aiming at the problem of frequent gas overrun in working face during mining higher slice in thick andhigh–gas seams, on the basis of destruction extent and transport mechanisms of relieved gas in lower slice underthe action of disturbance stress, gas extraction with kilometer hole in lower slice was studied with the backgroundof working face 205 in Tingnan mine. Theoretical calculation and FLAC3D numerical simulation indicate themaximum lower slice plastic failure depth is approximate 13 m, the optimal layout region of kilometer directionalhole is 6~9 m below the floor of working face. Monitoring the gas extraction concentration of kilometer drilling inhole positions in the process of working face advancing shows kilometer hole with optimal extraction effect is between6 m and 9 m, gas extraction concentration in drilling field continues to increase with working face advancing,and finally increases to approximately 68%. The study realized long–time and high concentration extraction inlower slice of thick and high–gas seams.