低透气性煤层顺层钻孔有效抽放半径的测定

Measurement of effective radius of gas drainage of bedding drill hole in low permeability coal seam

针对长平煤矿3号煤层低透气性的特征,通过改进封孔工艺,采用聚氨酯-膨胀水泥二次封孔方式,利用孔压法对该矿顺层钻孔瓦斯有效抽放半径进行了测定分析,准确测出了该矿顺层钻孔的有效抽放半径为2.5m,避免了瓦斯抽放过程中可能出现的空白区和串孔、塌孔现象,为该矿瓦斯抽放钻孔的施工布置提供重要依据。

In view of low permeability characteristics of No.3coal seam in Changping Coal Mine,the effective radius of gas drainage of bedding drill hole was measured and analyzed by improving sealing process with polyurethane-expansive cement and use of hole pressure method,and determined effective radius of gas drainage of bedding drill hole of No.3coal seam of Changping Coal Mine is 2.5meters.It avoids the phenomenon of empty gas drainage area,string holes and hole collapse in gas drainage process,and provides an important basis for reasonable arrangement of gas drainage drill hole.