基于“钻孔-巷道”双卸压圈的首采面瓦斯治理研究

Gas control in first working face based on borehole-roadway double stress relief rings

针对首采工作面回采初期瓦斯抽采困难的问题,分析了巷道、钻孔施工后周围岩层的变形及卸压情况,建立“钻孔-巷道”双卸压圈模型,计算钻孔和巷道之间任意点的瓦斯应力,得到该点处瓦斯的流动质量方程,从而提出高抽巷内施工下向钻孔抽采瓦斯方案,并对下向钻孔的打孔难题提出了相应对策,最终在1301首采工作面进行工程试验。研究结果表明:回采工作面初次来压步距为22m,而在工作面推进12m左右,高抽巷的瓦斯浓度就已经开始增加;工作面回采期间没有发生瓦斯超限、断电现象。因此,高抽巷内施工下向钻孔瓦斯抽采方案解决了首采工作面抽采初期瓦斯超限问题,证明了“钻孔-巷道”双卸压圈模型是合理的、可行的,对于首采面的瓦斯治理具有指导意义。

Aiming at the difficulty of gas extraction at the initial stage of mining in the first mining face,the deformation and pressure relief of the roadway and surrounding rock formations after the drilling construction were analyzed,and the boreholeroadway model of the double pressure relief ring was established to calculate the gas pressure at any point between the borehole and the roadway,and obtain the gas flow quality equation at this point,so as to propose the gas extraction scheme of the downward drilling in the high-level extraction lane and countermeasures for the problems in downward drilling.The technology was tested in the 1301 first working face,and the results showed that,the gas concentration and amount begin to rise 10m ahead of the initial weighting position;there is no gas over-limit or power outage during the working face mining.Therefore,the downward drilling gas extraction scheme in the high-level extraction lane solves the gas problem in the initial mining face,which proves that the drilling-roadway double pressure relief ring model is reasonable and feasible.