近距离上保护层开采工作面瓦斯涌出及瓦斯抽采参数优化

Gas emission and parameter optimization of gas extraction in mining face of short distance protective seam

为确保近距离上保护层工作面的开采安全,同时有效抽采下被保护层的卸压瓦斯消除其突出危险性,开展了近距离上保护层开采工作面的瓦斯涌出规律研究,在此基础上对被保护层的卸压瓦斯抽采参数进行了优化。研究结果表明:下被保护层12煤层位于上保护层开采后形成的底臌断裂带内,层间裂隙发育充分,保护层工作面瓦斯涌出量大多来自被保护层的卸压瓦斯;在采用底板岩巷上向网格式穿层钻孔对被保护层进行卸压瓦斯抽采时,被保护层卸压瓦斯流向保护层工作面还是穿层钻孔由瓦斯在裂隙中流动形成的沿程阻力决定;被保护层12煤层穿层钻孔间距确定为1倍层间距大小,即穿层钻孔间距为16m。工程应用表明,该设计参数能够满足保护层安全开采及被保护层消除突出危险性的要求。

In order to ensure mining safety of short distance protective seam face,and simultaneously to extract pressure relief gas from the lower protected seam and eliminate outburst risk,researched gas emission law in the mining face of short distance protective seam,and optimized extraction parameters of pressure-relief gas from the lower protected seam.The results show that the 12th coal seam of the lower protected seam is in the floor heave fracture zone which is formed after mining upper protective seam,fractures develop well and the amount of gas emission in mining face of protective seam is mainly from pressure-relief gas of the protected seam;when using net-like upward penetrating borehole to extract pressure relief gas from the lower protected seam,frictional resistance formed by gas flow in fracture determines the flow direction whether the pressure relief gas flow into mining face or penetrating boreholes;and the spacing between every two boreholes in the 12th coal seam of protected seam is determined as a single spacing between protective seam and protected seam,that is to say,16 m.Engineering application shows that the design parameters can meet the demands of mining safety in the protective seam and eliminating the outburst risk of the protected seam.