基于数值模拟方法的近断层巷道稳定性影响研究

Influence of near-fault roadway stability based on numerical simulation method

  • 摘要: 煤矿开采过程中,巷道围岩稳定性受多种地质因素影响,其中断层构造对巷道变形破坏的影响尤为关键。
    目的及方法 本研究以三元煤矿4326工作面为工程背景,采用FLAC3D数值模拟软件模拟采动影响下临近断层区与无断层区工作面巷道变形破坏情况,在此基础上研究巷道开挖支护围岩的变形破坏规律。
    结果及结论 研究结果表明,断层扰动致340 m埋深临近区竖向应力升至8.9~9.2 MPa,较无断层区高4.7%~8.2%,非对称场致围岩变形存在差异;近断层区巷道围岩变形量大于无断层区。掘进面超断面14 m后,近断层区顶底板垂直位移111.6 mm,比无断层区高58.8%;两帮水平位移煤柱侧100.4 mm、实体侧55.6 mm,分别增加79.3%和75.4%。断层使巷道围岩变形加剧,水平位移增幅更显著;断层还导致巷道围岩塑性区深度扩展,无断层区与近断层区相比,底板、煤柱帮和实体帮塑性区破坏深度分别扩展50%、40%和33.3%,断层主要影响底板和两帮塑性区扩展,顶板破坏深度受影响较小。

     

    Abstract: During the coal mining process, the stability of roadway surrounding rock is affected by various geological factors, among which the influence of fault structures on roadway deformation and failure is particularly critical. Taking the 4326 working face of Sanyuan Coal Mine as the engineering background, we use the FLAC3D numerical simulation software to simulate the deformation and failure of working face roadways in fault-proximity areas and fault-free areas under mining influence, and study the deformation and failure laws of surrounding rock after roadway excavation and support. The research results show that: the fault disturbance causes vertical stress in the adjacent area at a burial depth of 340 m to rise to 8.9~9.2 MPa, which is 4.7%~8.2% higher than that in the fault-free area. The asymmetric stress field leads to differences in surrounding rock deformation; the deformation of roadway surrounding rock in the near-fault area is greater than that in the fault-free area. After the driving face exceeds the section by 14 m, the vertical displacement of the roof and floor in the near-fault area is 111.6 mm, 58.8% higher than that in the fault-free area; the horizontal displacements of the two sides are 100.4 mm on the coal pillar side and 55.6 mm on the solid side, increasing by 79.3% and 75.4%, respectively. Faults aggravate the deformation of roadway surrounding rock, and the increase in horizontal displacement is more significant; faults also lead to the expansion of the plastic zone depth of roadway surrounding rock. Compared with the fault-free area, the failure depths of the plastic zone in the floor, coal pillar side and solid side are expanded by 50%, 40% and 33.3% respectively. Faults mainly affect the expansion of the plastic zone in the floor and two sides, and the failure depth of the roof is less affected.

     

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