大采高工作面接续开采覆岩稳定性数值模拟研究

Numerical simulation on overburden stability during successive mining of large mining height working faces

  • 摘要: 【目的及方法】针对大采高工作面接续开采的围岩稳定性问题,采用Phase 2D有限元软件建立数值模型,系统研究不同采高下覆岩塑性区演化、地表沉降、顶板下沉及保护煤柱应力分布规律。【结果】结果表明,随着开采扰动的增大,覆岩破坏范围及变形程度逐渐增大。当采高为5 m时,首采面开采后覆岩塑性区破坏单元数量为547个,次采面开采后激增至3984个,塑性区呈“上宽下窄”的拱形特征向顶板扩展;地表最大沉降量从0.14 m提升至0.52 m;顶板下沉量由0.30 m增至0.65 m;保护煤柱支承压力峰值从58.36 MPa增至130.16 MPa。随着采高的增大,大采高接续工作面开采覆岩稳定性降低。当采高由3 m增大至5 m时,覆岩塑性区破坏单元数增加107%,地表沉降量增加271%,顶板下沉量增加282%,保护煤柱支承压力增高系数由3.68增至8.38。【结论】研究揭示了采高及工作面接续开采对覆岩稳定性的显著影响,对工程实践具有一定参考价值。

     

    Abstract: To address the stability issues of surrounding rock during successive mining in large-height mining faces, this study establishes a numerical model using Phase 2D finite element software to systematically investigate the evolution characteristics of plastic zones in overburden strata, surface subsidence, roof convergence, and stress distribution in protective coal pillars under different mining heights. The results demonstrate, With the increase of mining disturbance, the scope of overburden failure and the degree of deformation gradually increase. When the mining height is 5 m, the number of failure units in the overburden plastic zone is 547 after the first mining face is mined, and surges to 3984 after the second mining face is mined. The plastic zone exhibits an arched feature of "wide upper part and narrow lower part" and expands toward the roof. The maximum surface subsidence increases from 0.14 m to 0.52 m; the roof subsidence increases from 0.30 m to 0.65 m; and the peak abutment pressure of the protective coal pillar increases from 58.36 MPa to 130.16 MPa. Enhanced mining heights significantly reduce overburden stability during successive mining operations. When mining height increases from 3 m to 5 m, the plastic failure units increase by 107%, surface subsidence escalates by 271%, roof convergence amplifies 282%, and the abutment pressure coefficient in coal pillars rises from 3.68 to 8.38. This research reveals the substantial impacts of mining height and face succession on overburden stability.

     

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