综放工作面强动压巷道围岩综合控制技术研究与应用

Research and application of comprehensive surrounding rock control technology for strong dynamic pressure roadway in longwall top-coal caving face

针对老石旦煤矿强烈动压影响巷道围岩变形难题,在分析顶板岩层以及地应力场分布的基础上,总结了动压巷道围岩的变形破坏特征,提出了水力压裂卸压与高预应力锚杆支护的协同控制技术,确定了最佳压裂高度,制定了水力压裂方案与高预应力锚杆支护方案,开展了井下工程应用。结果表明:水力压裂有效激发了顶板岩层破裂和裂缝扩展,形成大尺度裂缝,阻断了侧向支承压力的传递路径;巷道矿压显现明显减弱,顶底板移近量402 mm,两帮移近量83 mm,较原支护变形显著减小;强采动影响下锚杆(索)受力变化趋势明显减弱,锚杆最大受力79~96.5 kN,锚索最大受力101 kN,且未发生锚杆(索)破断现象,表明采用水力压裂与高预应力锚杆支护后,巷道围岩侧向支承压力明显减弱,稳定性显著提高,强动压巷道围岩控制效果显著。

Aiming at the roadway surrounding rock deformation under strong dynamic pressure in Laoshidan Coal Mine,by analyzing the distribution of roof strata and geostress field,the deformation and failure characteristics of roadway surrounding rock under dynamic pressure was summarized;then,a collaborative control technology of hydraulic fracturing pressure relief and high prestressed bolt supporting was proposed;the optimal fracturing height was determined;and a hydraulic fracturing scheme and a high prestressed bolt supporting scheme were developed;finally,the technology was applied in underground engineering.The results show that,the hydraulic fracturing effectively stimulated the roof rock fracture and crack propagation,forming large-scale fractures,and blocking the transmission path of lateral abutment pressure;the mine pressure behavior in the roadway was significantly weakened,with the displacement of the roof and floor being 402 mm,and the displacement of the two sides being 83 mm,significantly reducing the deformation compared to the original supporting;under the strong mining influence,the stress variation of bolt and cable was significantly weakened,with a maximum stress of 79~96.5 kN for the bolt and 101 kN for the cable,and no breakage of the bolt or cable occurred.The results indicate that,after implementing the proposed technology,lateral abutment pressure of the surrounding rock was significantly weakened,the stability was enhanced,and the surrounding rock control effect was remarkable under strong dynamic pressure.