全煤巷道顺层瓦斯抽采钻孔合理封孔深度研究

Reasonable Sealing Length of Gas Extraction Borehole in Full Coal Roadway

为了提高亭南矿顺层钻孔抽采瓦斯的效率,基于合理封孔深度的重要性,采用FLAC^(3D)模拟煤巷开挖后围岩塑性区、垂直应力分布情况,并用Tecplot软件提取巷帮煤岩垂直应力数值,拟合后得到距巷帮不同深度的应力分布曲线。根据钻屑法、钻屑瓦斯解吸指标法现场实测数据,确定出全煤巷道3个应力分区的范围。通过抽采效果验证,证明顺层瓦斯抽采钻孔合理封孔深度是应该超出巷帮的卸压带或塑性区范围,但同时又应小于应力峰值点的深度。最终确定亭南矿顺层瓦斯抽采钻孔的合理封孔深度为9m。

In order to improve the efficiency of bedding gas drainage borehole of Tingnanmine,based on the importance of rational sealing depth,using numerical simulation software FLAC3 Dsimulates plastic zones and the vertical stress distribution case after coal roadway excavation. And using the Tecplot software to extract of the roadway coal and rock vertical stress values,and finally get the stress distribution curve away from roadway at different depths after fitting. According to drilling bits amount,cuttings gas desorption indexmethod field data,to determine the scope of the seam roadway three stress partition. Through the effect of extraction proof bedding reasonable sealing gas drainage drilling depth should be beyond the scope of relief with or plastic zone of two sides roadway,but also less than the peak stress point roadway depth. So the rational borehole sealing depth of Tingnanmine is 9m.