水力冲孔造穴增透机制及应用研究

Research on mechanism and application of hydraulic punching hole to increase permeability

为研究水力冲孔造穴技术的卸压增透机制,利用受载煤体全应力—应变曲线,建立受载煤体渗透率演化模型,结合Comsol Multiphysics多物理场数值模拟软件,验证了水力冲孔造穴对煤体卸压增透的有效性。结果表明:水力冲孔造穴技术在形成半径为0.60 m的空洞后,在钻孔周围煤体内形成了半径为1.34 m的瓦斯渗透率增高区。该技术在焦煤集团九里山矿井下16051运输底抽巷开展试验,通过对普通钻区和冲孔造穴区的瓦斯抽采数据进行对比,可以看出:采取水力冲孔造穴措施后,抽采钻孔的瓦斯浓度提高了0.77倍,瓦斯抽采纯量提高了1.51倍,该措施有效地提高了煤层瓦斯抽采效率,减少了安全事故,保证了工作面的安全回采。

In order to study the pressure relief and permeability enhancement mechanism of the hydraulic punching and cavitation technology,the full stress-strain curve of the loaded coal body was used to establish the permeability evolution model of the loaded coal body.Combining with the multi-physics numerical simulation software of Comsol Multiphysics,the effectiveness of hydraulic punching and cavitation on coal pressure relief and permeability enhancement was verified.The results showed that the hydraulic punching and cavitation technology forms a gas permeability increased zone with a radius of 1.34 m in the coal body around the borehole after forming a cavity with a radius of 0.60 m.The technology was tested in the 16051 transportation bottom extraction roadway under the Jiulishan Mine of the Jiaozuo Coal Group.By comparing the gas drainage data of the ordinary drilling area and the punching and cave-making area,it could be seen that after the hydraulic punching and cave-making measures were taken,the pumping gas concentration of the drilled hole was increased by 0.77 times and the gas extraction pure volume was increased by 1.51 times.This measure effectively improved the gas drainage efficiency of the coal seam,reduced safety accidents and ensured the safe mining of the working face.