穿层钻孔割缝混合强化预抽煤巷条带消突机制研究及应用

Research and application of gas outburst prevention mechanisms through combining gas drainage slotted boreholes and ordinary boreholes in coal roadways

针对普通钻孔网格式布置掩护煤巷掘进增透效果差、卸压不充分的问题,提出了穿层钻孔割缝混合强化预抽煤巷条带消突技术,研究了其增透卸压消突机制,并进行了现场应用。研究结果表明,高压水射流冲击应力波反射形成的径向拉力对裂缝系统的生成起着关键作用,可以预置弱面增强其反射作用。普通孔对割缝孔卸压带的延伸起到了导向作用,而割缝孔对普通孔卸压带的扩展起到了激励作用,割缝孔和普通孔的卸压带相互连接形成整体卸压。现场试验结果表明,煤层透气性及钻场抽采平均纯流量大幅度提升,措施后掘进工作面防突预测指标未出现超标现象,消突效果明显。

Research and application of technologies to address gas drainage in roadways through the use of a combination of slotted boreholes and ordinary boreholes was undertaken. The objective was to address poor outcome effects of permeability enhancement and insufficient pressure relief in ordinary borehole grid layouts covering coal roadway tunnels. The mechanism of pressure relief and permeability enhancement was studied and a field test was carried out. The test revealed that the radial tensile stress formed by reflection of a high-pressure water jet impact stress wave was crucial for the generation of a fracture network. Enhanced reflection effects were achieved by pre-setting the weaker surface. The ordinary boreholes play a guiding role in the extension of the slotted boreholes＇ distress zone and the slotted boreholes play an important role in the expansion of the ordinary boreholes＂ distress zone. The interconnection of the distressed zones forms the total pressure relief. The field test indicated that the coal seam permeability and the average flow increased significantly and the predictive indexes were not exceeded. This has proven that the effect of outburst elimination is evident.