余吾煤矿巷道围岩应力分布及封孔深度优化

Stress Distribution of Roadway Surrounding Rock and Optimization of Sealing Depth in Yuwu Coal Mine

以余吾煤矿N1100工作面为研究对象,结合FLAC^(3D)数值模拟和钻屑法实测分析了巷道围岩应力分布规律,并基于此确定了抽采钻孔合理封孔深度。结果表明:余吾煤矿N1100工作面巷道距巷帮深度0~10.5 m为卸压区,距巷帮14.5 m为应力峰值点,巷道塑性区深度为14.5 m。围岩应力分布是决定钻孔封孔深度的重要因素,钻孔瓦斯抽采浓度随封孔深度增大呈先减后增的规律。综合对比不同封孔深度条件下的钻孔瓦斯抽采浓度和抽采纯量,确定余吾煤矿N1100工作面的合理封孔深度为12~14 m。

Taking N1100 working face of Yuwu coal mine as the research object, based on FLAC^(3D) numerical simulation and drilling cuttings insitu measurement, the stress distribution of roadway surrounding rock is studied, and the reasonable sealing depth of gas drainage borehole is determined.The results show that the depth of pressure relief zone is between 0 and 10.5 m away from the side of roadway in N1100 working face of Yuwu coal mine, and the peak stress point is 14.5 m away from the side of roadway, the depth of plastic zone of the roadway is 14.5 m. The distribution of stress in the surrounding rock of roadway is an important factor to determine the depth of hole sealing, and the gas extraction concentration of borehole decreases first and then increases with the increase of sealing depth. The reasonable sealing depth in N1100 working face of Yuwu coal mine is between 12 and 14 m by comparing the gas extraction concentration and pure amount of drilling under the conditions of different hole-sealing depth.