深孔预裂对采空区瓦斯抽采效果的影响研究

Research on gas drainage effect in goaf by deephole presplitting

针对大跨度工作面采空区坚硬顶板悬而不落易造成瓦斯超限的问题,以潞宁煤矿地质条件为工程背景,运用数值模拟、现场测试等方法开展了采空区瓦斯治理研究。FLAC 3D模拟结果表明:顶板未采取任何处理措施时初次来压步距达到了60 m。基于深孔爆破和采空区高位钻孔抽采原理,现场试验结果表明:采取深孔预裂后,工作面倾向来压步距不同步,初次来压步距减小为31~45 m;来压后,高位钻孔最高瓦斯抽采浓度、纯流量增加了1.8倍、5.6倍;顶板来压对高位钻孔和插管抽采均具有促进作用,但对高位钻孔抽采影响程度更明显,且来压后瓦斯治理主要以抽采为主。

Aiming at the problem of gas overlimit caused by hard roof suspension in goaf of long span working face,taking the geological condition of Luning mine as engineering background,the study on gas control in goaf is carried out by numerical simulation and field test.The results of FLAC 3D simulation show that the initial step distance reaches 60 m when no treatment measures are taken on the roof.Based on the principles of deep hole blasting and high level borehole extraction in goaf,the field test results show that the working surface incline to step distance is out of synchronization after the deep hole presplitting,and the initial step distance is reduced to 31-45 m.After the pressure is applied,the maximum gas drainage concentration and pure flow rate of the high-level drilling hole increased by 1.8 times and 5.6 times.The roof pressure can promote the extraction of high borehole and intubation,but the impact on the high-level drilling is more obvious,and the gas control is mainly based on the extraction after the pressure.