偏应力不变量对深部采动巷道围岩的影响及工程应用

Influence of deviatoric stress invariants on the surrounding rock of deep mining roadways and its engineering applications

  • 摘要: 在不同水平应力作用下,深部巷道围岩的力学行为变得十分复杂,传统的二维应力分析方法基于平面应变假设,未能准确反映深部巷道围岩的真实力学行为和塑性变形模式,尤其是忽略了中间主应力的影响。基于弹塑性力学理论及前人对三维应力分析的研究成果,并考虑泊松效应,进一步推导了偏应力第二不变量J2及第三不变量J3的解析解。通过数值模拟研究了不同水平应力下,深部巷道围岩偏应力不变量的分布特征及其演化规律,揭示了复杂三向应力作用下围岩偏应力不变量对塑性区演化的影响机制,分析了不同水平应力下围岩偏应力分布对塑性区范围和形态的影响:水平应力的变化显著影响J2J3的分布和塑性区的形态,径向水平应力决定了J2J3的形态演化,轴向水平应力决定了J2J3的峰值变化,尤其在较高水平应力条件下,围岩稳定性受到更大挑战。结合实际工程,以三向应力大小相近的深埋近水平巷道为案例验证回采过程中围岩非对称变形破坏特征,建立数值模型对巷道围岩的J2J3分布及塑性区扩展特征进行了验证研究,并为应对非对称偏应力条件下的围岩变形,提出了超前支架、锚杆(索)组合支护技术。通过现场监测验证,证明该支护措施能显著控制巷道围岩的变形和破坏,提高巷道的整体稳定性和安全性。

     

    Abstract: The mechanical behavior of surrounding rock in deep roadways becomes highly complex under different horizontal stresses. Traditional two-dimensional stress analysis methods cannot accurately capture the true mechanical response. Elastoplastic mechanics theory and previous research on three-dimensional stress analysis are built upon. It also incorporates the Poisson effect to further derive analytical solutions for the second (J2) and third (J3) deviatoric stress invariants. The distribution and evolution of J2 and J3 under different horizontal stresses are then examined. Numerical simulations reveal how changes in the horizontal stress ratio significantly affect the distribution of deviatoric stress and the shape of the plastic zone. These effects are especially pronounced at higher horizontal stress ratios, where the stability of surrounding rock faces greater challenges. A numerical model is established to simulate the distribution of J2 and J3 and the expansion of the plastic zone around the roadway. Based on these findings, a combined support technology using advanced supports and rock bolts (cables) is proposed for asymmetric deviatoric stress conditions. Monitoring results confirm that this support strategy effectively controls rock deformation and failure, thereby enhancing overall roadway stability and safety.

     

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