基于Mogi-Coulomb准则的围岩抗力系数新解

New Solution of Rock Resistant Coefficients Based on the Mogi-Coulomb Failure Criterion

  • 摘要: 围岩抗力系数是水工压力隧洞等地下结构进行支护设计的重要参数。文章基于可考虑中间主应力对围岩强度提高作用的Mogi-Coulomb准则以及经典的理想弹-塑性材料模型, 推导了深埋圆形隧道围岩应力和位移的解析解, 进而得到围岩弹塑性抗力系数新解, 最后对所得解答进行比较与验证, 并探讨了围岩强度参数的影响特性。研究结果表明: 文章基于Mogi-Coulomb准则的围岩抗力系数新解介于文献Matsuoka-Nakai(SMP)准则解答和Lade-Duncan准则解答之间, 且三者相差不大;Mohr-Coulomb准则解答却明显偏小, 考虑中间主应力可以更加充分发挥围岩的荷载分担能力;粘聚力及内摩擦角对围岩抗力系数的影响显著, 且内摩擦角对其影响更明显。

     

    Abstract: The rock resistant coefficient is one of the important parameters in the support design of underground structures such as hydraulic tunnels. Based on the ideal elastic-plastic material model and the Mogi-Coulomb failure criterion, which considers the role that intermediate principal stress plays in increasing strength of the surrounding rock, an analytical solution of stress and displacement of the surrounding rock around a deep buried circular tunnel is derived, and a new solution for the rock elastic-plastic resistant coefficient is obtained. Lastly, the effects on rock strength parameters are studied after the comparison and verification of all the solutions. The results show that the new solution for the rock resistant coefficient based on the Mogi-Coulomb failure criterion is between the solutions of Matsuoka-Nakai (SMP) failure criterion and the Lade-Duncan failure criterion, with little differences; as the solution of the Mohr-Coulomb failure criterion is obviously smaller than the other ones, the consideration of intermediate principal stress could give full play to the load sharing capability of the surrounding rock; and the cohe? sion and inner friction angle have great influence on the rock resistant coefficient, and the influence of the inner friction angle is more obvious.

     

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