瓦斯抽采钻孔合理封孔长度研究

Study on Rational Sealing Length of Boreholes in Gas Extraction

针对煤矿巷道开挖之后,巷道围岩一定范围内为应力降低区(即巷道松动区),高突矿井进行瓦斯抽采钻孔封孔时,封孔段如果处在松动区范围,巷道内的空气会通过围岩裂隙进入抽采管,导致抽采浓度偏低的问题,运用FLAC^(3D)数值模拟和钻屑量法对巷道围岩应力分布进行了研究,进而确定瓦斯抽采钻孔合理封孔长度。

After the excavation of coal mine roadways, surrounding rock will become a stress reduced zone （or loosening zone of roadway） within a certain range. When boreholes are sealed during gas extraction in high-outburst mines, if the sealing section is in the loosening area, the air in the roadway will enter the extraction pipe through the fissures of the surrounding rocks, re- sulting in low gas concentration. The stress distribution of the surrounding rock is studied by the numerical simulation with FLAC3D and drill-cutting-weight method to determine the rational seal- ing length of the boreholes in the gas extraction.