轴对称荷载作用下圆形隧道围岩变形解析

Analytic solutions for surrounding rock mass deformation of circular tunnels subjected to axisymmetric loads

根据隧道开挖后围岩中三向应力状态的渐变规律,分析了围岩的变形特性,对隧道围岩进行了合理分区.基于双剪统一强度理论中针对岩土材料提出的双剪三参数准则,推导了轴对称荷载下圆形隧道围岩中塑性区应力场、应变场、支护力和塑性区半径的解析解.经实例分析表明,所选强度理论符合岩体材料自身特殊的强度特性,考虑了中间主应力的影响,分析结果贴近围岩的真实状态.

According to the gradual deformation principle of surrounding rock mass under the in-situ three-dimensional stress condition after tunnel excavation, the deformation characteristics of the rock mass was analyzed and the rock mass was zoned rationally. It is assumed that the rock mass is governed by the twin shear stress three-parameter criterion in the unified strength theory. The analyti- cal solutions of some factors were deduced under axisymmetric loads, including the stress field, strain field, support force and plastic radius in the plastic zone. The case analysis result shows that this selected strength theory matches to the actual strength characteristics of the rock mass due to taking the effect of intermediate principal stress into account.