基于Mogi-Coulomb强度准则的隧道围岩理想弹塑性解答

合理选择岩石强度准则对隧道应力及位移预测和支护设计都具有重要意义,基于MogiCoulomb强度准则和理想弹塑性模型,通过中间主应力系数反映中间主应力的影响,推导了圆形隧道围岩应力和位移的解析解,并对所得结果进行比较与验证,得到了中间主应力和围岩抗剪强度参数的影响特性。研究表明:具有广泛的适用性和较好的可比性,Mohr-Coulomb强度准则解答和Matsuoka-Nakai准则解答均为其特例;结果关于中间主应力系数b=0.5对称,较好地反映了岩石强度的中间主应力效应及其区间性;粘聚力及内摩擦角对围岩塑性区半径和隧道洞壁位移的影响显著,应充分考虑中间主应力影响及围岩抗剪强度参数变化对隧道设计与施工的影响。

Elastic-Perfectly Plastic Solution of Tunnel Surrounding Rocks Using Mogi-Coulomb Strength Criterion

Reasonable choice of rock strength criteria is crucial for stress and displacement prediction and support design in tunnel engineering. Based on Mogi-Coulomb strength criterion and elastic-perfectly plastic model, analytical solutions of stress and displacement for surrounding rocks around a circular tunnel were derived The intermediate principal stress coefficient was used to present the intermediate principal stress effect. The results in this study were compared with the current solutions in the literatures and the influence of intermediate principal stress and shear strength parameters of surrounding rocks was discussed. The results showed extensive applicability and the Mohr-Coulomb strength criterion and Matsuoka-Nakai criterion are two special cases; when the intermediate principal stress coefficient b was equals to 0.5, the results indicated that the intermediate principal stress effect and its range for rock strength; the influence of cohesion and internal friction angle on the plastic radius and tunnel wall displacement was significant; Care should be taken to the effects of intermediate principal stress and shear strength parameter variations of surrounding rocks on tunnel design and construction.