考虑中主应力和剪胀的深埋圆形隧道黏弹塑性蠕变解

深埋圆形隧道的开挖支护是与时间相关的复杂力学过程。为了描述这一过程，假设隧道围岩为Burgers体与Drucker-Prager准则组合的黏弹塑性模型。隧道开挖支护完成瞬时围岩表现为弹塑性，此时考虑中主应力的影响，推导出原岩应力和支护反力共同作用下的应力场；随后，假设此应力场保持不变，隧道围岩表现出随时间变化的蠕变性能，进一步推导出深埋圆形隧道考虑剪胀性能的围岩蠕变位移解析式；结合实际算例，分析围岩剪胀角与支护反力对深埋圆形隧道围岩蠕变位移的影响规律。结果表明，剪胀角的变化会对隧道围岩蠕变位移产生较大影响，而支护反力并不能完全控制高地应力作用下的深埋隧道围岩位移随时间的持续增加。

VISCOELASTOPLASTIC CREEP SOLUTIONS TO DEEP CIRCULAR TUNNELS CONSIDERING INTERMEDIATE PRINCIPAL STRESS AND SHEAR DILATANCY

The excavation and supporting of a deep circular tunnel is a complex mechanical process related to time. To describe this process，the surrounding rock of the tunnel is supposed to a viscoelastoplastic combination model of a Burgers body and Drucker-Prager criterion. At the instant time that the excavation and supporting were finished，the surrounding rock of the tunnel performs as a elastoplastic material. Under this condition，the influence of intermediate principal stress was considered，and the stress field under the combined action of the primary rock stress and supporting force could be obtained. With the assumption of constant stress field，the surrounding rock exhibits creep properties of time-dependence. Furthermore，the analytical solution to the creep displacement of the surrounding rock was deduced considering shear dilatancy for the deep-buried circular tunnel. A practical engineering instance was given and the regularities that the supporting force and dilation angle of the surrounding rock affect the creep displacement in deep circular tunnel were analyzed. The results show that the change of dilation angle could produce significant influence on the creep displacement，while the supporting force could not completely control the sustained increase of displacement of the surrounding rock with time in the deep circular tunnel.