基于数值模拟和现场测试的中厚煤层切顶留巷关键技术研究

Key technology of roof-cutting and entry-retaining of medium-thick coal seam based on numerical simulation and field test

  • 摘要: 为探究切顶卸压沿空留巷技术在浅埋深中厚煤层的应用效果,结合理论分析、数值模拟、现场监测等手段对金通煤矿51112工作面浅埋深中厚煤层切顶留巷关键技术参数展开研究。首先,对工作面概况和巷道支护形式进行了调研,51112工作面埋深平均55 m,煤层厚度为3.2 m,为典型的浅埋深中厚煤层软弱顶板,并对巷道围岩变形特征进行了分析;以此为基础,结合该工作面中厚煤层软弱顶板,分别对顶板切缝、聚能爆破、恒阻锚索支护、挡矸支护、架后临时支护等关键技术相关参数进行分析设计,确定出最佳的关键技术参数;然后通过不同切缝高度的数值模拟确认了最佳切缝高度为9 m,通过不同切缝角度的数值模拟确认了最佳切缝角度为15°,然后将设计的留巷技术参数进行现场应用。最后结合现场监测数据进行分析并验证,现场留巷监测结果显示,工作面卸压效果明显,最终留巷顶底板移近量为233 mm,两帮收敛量为150 mm,围岩变形可控,成巷效果显著,有效断面尺寸足以满足相邻工作面复用需求。

     

    Abstract: In order to investigate the application effect of roof-cutting and pressure relief gob-side entry returning technology in shallow buried deep and medium-thickness coal seam, combining theoretical analysis, numerical simulation, on-site monitoring and other means, we carried out study on the key technical parameters of shallow buried deep and medium-thickness coal seam roof-cutting entry-retaining in the 51112 working face of Jintong Coal Mine.First, the working face and roadway support form was investigated: 51112 working face's average buried depth is 55 m, the thickness of the coal seam is 3.2 m, with the typical shallow buried deep medium-thickness coal seam with soft weak roof, and the roadway deformation characteristics of the surrounding rock was analyzed; the key technologies-related parameters of roof cutting slit, cumulative energy blasting, constant resistance anchor cable support, blocking gangue support, and racking temporary support were designed, and optimum parameters were determined; then the optimal slit height of 9 m was confirmed through the numerical simulation of different slit heights, and the optimal slit angle of 15° was confirmed through the numerical simulation of different slit angles, and then the designed technical parameters of the retaining roadway were applied in the field.The on-site monitoring results show that the pressure relief effect of the working face is obvious, the final convergence of the roof and floor of the entry retaining is 233 mm, and the convergence of the two sides is 150 mm, the deformation of the surrounding rock is controllable, the effect of the roadway formation is remarkable, and the effective section size is enough to meet the reuse requirements of the adjacent working face.

     

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