煤与瓦斯突出矿井工作面顶板高位钻孔优化设计

Optimized Design on High Level Borehole in Roof of Coal Mining Face in Coal and Gas Outburst Mine

为提高瓦斯抽采率,基于采场围岩裂隙发育特征及瓦斯流动规律,采用UDEC数值模拟软件模拟祁南煤矿342工作面在推进时的覆岩裂隙发育规律,优化工作面顶板高位钻孔设计方案。研究结果表明:当工作面推进速度5 m/d时,裂隙发育和瓦斯积聚区距煤层顶板12~22 m,在高位钻孔的层位控制范围,高位钻孔倾向控制范围优化为距回风巷9~36 m,钻场间钻孔的压茬距离35 m。祁南煤矿342工作面顶板高位钻孔按优化方案设计施工,单孔最大瓦斯抽采体积分数达84%,高位钻孔瓦斯抽采率达50%以上,工作面回风流的瓦斯体积分数控制在0.6%以下,保证了工作面的安全开采。

In order to improve the gas drainage rate,based on crack development features of the surrounding rock in the coal mining face and the gas flow law,the UDEC numerical simulation software was applied to simulate the crack development law of the overburden strata during No.342 coal mining face in Qinan coal mine pushing forward and an optimized design plan of high level boreholes in the roof of the coal mining face was provided.The study results showed that when the pushing forward speed of the coal mining face was 5 m/d,the crack development and gas accumulation zone with a distance of 12~22 m to the seam roof would be a layer control scope of the high level bore-holes.An inclined control scope of the high level borehole was optimized to have a distance of 9~36 m to the air return gateway and a cross distance of the boreholes in the drilling site would be 35 m.The high level boreholes in the roof of No.342 coal mining face in Qinan Mine were designed and constructed based on the optimized plan.The max gas drained concentration of a single borehole was 84%,the gas drain-age rate of the high level boreholes was over 50%,the gas volume fraction of the return current in coal mining face was controlled below 0. 6% and the safe mining of the coal mining face was ensured.