中文摘要：

该文基于广义空间准滑动面SMP（Spatial Mobilized Plane）强度准则，对圆形隧洞围岩的应力和位移，得到了可考虑中间主应力和材料脆性软化影响的弹塑性解和弹．脆．塑性解，给出了隧洞围岩的应力、位移、临界支护力与塑性区半径的表达式。通过将该文的弹塑性解与经典的圆形隧洞弹塑性解（卡斯特纳解）进行对比，验证了建立的公式的正确性，同时通过与基于Mohr-Coulomb强度准则的弹．脆．塑性解析解进行对比：论证了中间主应力和材料脆性软化对围岩稳定性的影响显著，考虑中间主应力的影响可以发挥围岩的强度潜能，能使围岩的强度和变形规律更接近工程实际，所得成果有重要参考价值。

英文摘要：

Based on the extended Spatial Mobilization Plane Criterion （SMP）, an elastic-brittle-plastic solution for an axisymmetric cylindrical tunnel was established, in which the influence of both intermediate principal compressive stress and material strain-softening behavior was considered, and the closed-form formulas of critical support force, the radius of a plastic zone, the distribution of stresses and displacements in surrounding rock were put forward. The elastic-plastic solution based on SMP was compared with Kastner solution, by which the rightness of the obtained elastic-plastic solution was verified. Also a comparative study between the elastic-brittle-plastic solution by obeying SMP and the current solution based on Mohr-Coulomb Criterion was made, including the examination of the influences of material strain-softening rate and intermediate principal stress. The results indicate that the rock strain-softening rate and the intermediate principal stress have a considerable effect on the stability analysis of surrounding rock, from which the strength potentials of rock mass can be used further, and it is also helpful for the design optimization of a tunnel support system.