厚煤层巷道围岩动力失稳及抗冲击支护优化策略研究

    Research on power instability of surrounding rock and optimization strategy of anti-impact support for thick coal bed roadway

    • 摘要: 围绕厚煤层巷道围岩动力失稳难题,通过结合弹性力学理论与冲击动力学原理,探究了动载应力波传播机制及支护结构动态响应规律,提出了巷道围岩抗冲击支护优化方案。研究表明:动载应力波传播历经初始应力扰动、主应力波动、应力场重构3个阶段演化过程;波动传播阶段锚固构件出现渐进式损伤,应力平衡阶段支护体系进入能量耗散稳定状态;围岩质点运动参数与冲击强度呈非线性增长关系;确立105 J为围岩动力失稳临界阈值,超限冲击将引发支护体系失效;全断面锚索梯度释能支护体系通过构建深浅协同承载结构,可提升顶板承载层等效刚度并降低锚索动力损伤率;优化方案实施后围岩裂隙扩展深度缩减60.1%~64.2%,收敛变形量下降49.8%~67.7%,支护结构完整性提高2.3倍。

       

      Abstract: Focusing on the problem of dynamic instability of the surrounding rock in the roadway of thick coal seam, by combining the theory of elasticity mechanics and the principle of impact dynamics, the propagation mechanism of the dynamic loaded stress wave and the dynamic response law of the supporting structure are investigated, and the optimization scheme of the anti-impact support for the surrounding rock in the roadway is put forward. The study shows that: the propagation of dynamic loaded stress wave goes through the initial stress disturbance stage, the main stress fluctuation stage, and the stress field reconstruction stage in three stages of the evolution process; the progressive damage of anchorage components occurs in the fluctuation propagation stage, and the support system enters into the stable state of energy dissipation in the stress equilibrium stage; the parameters of the movement of peripheral rock mass points and the impact intensity show a non-linear growth relationship; 105 J is established as the critical threshold of peripheral rock dynamic instability, and the impact of the over-limit will trigger the failure of the support system; the full-loaded stress wave propagation mechanism and dynamic response law of the support structure are investigated. The support system failure is triggered by the over-limit impact; the full-section anchor cable gradient energy release support system can improve the equivalent stiffness of the roof bearing layer and reduce the dynamic damage rate of the anchor cable by constructing the deep and shallow coordinated bearing structure; the depth of the perimeter rock fissure expansion is reduced by 60.1%~64.2% after the implementation of the optimized scheme, the convergent deformation is reduced by 49.8%~67.7%, and the integrity of the support structure is improved by 2.3 times.

       

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