深部仰采孤岛工作面初采期间冲击地压防治

    Prevention of rock burst during initial mining of deep overhand mining island working face

    • 摘要: 以霄云煤矿1310工作面为工程背景,通过计算判断悬顶初次破断失稳位置,分析坚硬顶板破断时释放的大量弯曲应变能,并利用FLAC3D数值模拟分析深部仰采孤岛工作面初采阶段的采动应力变化;基于悬顶破断释放的能量和初采期间应力集中系数超过发生冲击地压的临界值,判断深部孤岛工作面初采期间发生冲击地压的可能性较大;通过采取大直径钻孔卸压结合顶板深孔预裂爆破等综合卸压措施对初采阶段冲击危险性进行防治。结果表明:卸压钻孔形成的弱化带破坏了煤体承载结构,使靠近巷道的浅部煤体应力明显下降,且应力峰值向煤体深部转移;爆破对顶板进行损伤破坏,提前释放或转移了坚硬顶板积聚的弹性能,从而降低孤岛工作面初采阶段发生冲击地压的可能性。

       

      Abstract: Taking No.1310 working face of Xiaoyun Coal Mine as the engineering background, the initial breakage and instability position of the suspension roof was determined by calculation, the large amount of bending strain energy released was analyzed when the hard roof is broken, and FLAC3D numerical simulation was used to analyze the mining stress changing during the initial mining of the deep overhand mining isolated island working face. Based on the energy released by the breakage of the suspension roof and the stress concentration coefficient during initial mining exceeding the critical value of rock burst, it was judged that the rock burst was likely to occur during the initial mining of the deep isolated island working face. By taking comprehensive pressure relief measures such as large-diameter borehole pressure relief combined with roof deep hole presplit blasting and other comprehensive pressure relief measures, the impact risk in the initial mining stage was prevented and controlled. The results show that the weakened zone formed by the pressure relief drilling destroys the bearing structure of the coal body, which obviously reduces the stress of the shallow coal body near the roadway, and the stress peak shifts to the deep part of the coal body. Blasting damages the roof, releasing or transferring the elastic energy accumulated in the hard roof in advance, so as to reduce the possibility of rock burst in the initial mining stage of isolated island working face.

       

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