下部煤层回采巷道布置及支护技术工艺研究

Research on Stoping Roadway Layout and Support Technology Process of Lower Coal Seams

  • 摘要: 层间距较小煤层开采中,上部煤层扰动下的下部巷道支护稳定性是制约矿井安全生产的关键问题。针对固庄煤矿煤层间距较小导致支护难度大的技术难题,采用理论分析与数值模拟相结合的方法,研究下部回采巷道内错距离对围岩应力及塑性区的影响,划分<2 m、2~5.5 m、5.5~13.5 m及>13.5 m四种层间距工况,提出差异化支护方案:层间距<2 m采用“注浆+锚网+架棚”,2~5.5 m采用“锚网+架棚”,5.5 m以上采用“锚杆(索)+金属网”(参数差异化),并在1150轨道巷开展现场试验。结果表明:下部巷道内错距离为30 m时处于卸压区域,顶底板应力峰值分别为0.75 MPa和0.82 MPa,塑性区未贯通;现场监测显示,各工况下巷道围岩变形均可控,其中<2 m时顶底板及两帮最大变形量为162 mm和137 mm。研究确定30 m为合理内错距离,提出的方案满足安全生产需求,可为类似条件巷道支护提供技术参考。

     

    Abstract: In small spacing coal seam mining, the support stability of lower roadways under the disturbance of upper coal seams is a key problem that restricts the mine safety production. Aiming at the technical difficult problem of large difficulty in support caused by the small spacing between coal seams in Guzhuang Coal Mine, a combination method of theoretical analysis and numerical simulation is adopted to study the influence of the internal displacement in the lower stoping roadways on the surrounding rock stress and plastic zone. Four kinds of layer spacing working conditions are divided: <2 m, 2-5.5 m, 5.5-13.5 m, and >13.5 m, differentiated support schemes are proposed: "grouting+anchor mesh+shed" is adopted for layer spacing <2 m, "anchor mesh+shed" is adopted for layer spacing between 2-5.5 m, and "anchor rod (cable)+metal mesh" (parameter differentiation) is adopted for layer spacing above 5.5 m. On-site tests are carried out in the 1150 track roadway. The results show that when the lower roadway internal displacement is 30 m, it is in the pressure relief zone, with stress peak values of 0.75 MPa and 0.82 MPa on the roof and floor respectively, and the plastic zone is not penetrated; The on-site monitoring indicates that the deformations of the roadway surrounding rock are all controllable under various working conditions, with the maximum deformation amount of 162 mm and 137 mm for the roof, floor, and two sides when the layer spacing is <2 m. This research determines that the reasonable internal displacement is 30 m, and the proposed scheme meets the safety production requirements and can provide technical reference for roadway support with similar conditions.

     

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