为解决高地应力围岩挤压型大变形问题，根据以往挤压型大变形隧道案例，选取适用于泥岩、砂岩、粉质砂岩等各向同性软岩，利用Burgers模型和M-C塑性体串联形成的CVISC黏弹塑性模型，结合CVISC模型黏弹性元件和弹塑性元件相互独立的特性，将围岩径向位移分为瞬时弹塑性阶段位移和黏弹性阶段位移，分别推导塑性区和黏弹性区径向位移解析解，叠加组合形成围岩位移分布解析解，分析围岩径向位移场、应力场随时间变化规律，全面描述硐室变形规律。借助FLAC3D和相关文献理论解答验证其适用性，在此基础上进行长期变形的参数敏感性分析，结果表明各阶段最关键的3个参数分别是内摩擦角、黏聚力和弹性模量，蠕变参数仅在其控制阶段具有显著敏感度。
To control the large squeezing deformation of
surrounding rocks with high geostress, the CVISC viscoelasticplastic
model formed by the Burgers model and MC plastic body
in series is selected for isotropic soft rocks such as mudstone, sandstone, and
siltstone based on the previous tunnel cases with large squeezing deformation.
The radial displacement of the surrounding rock is divided into instantaneous
elasticplastic phase displacement and viscoelastic
phase displacement using the independent properties of viscoelastic and elasticplastic elements of the CVISC model. The analytical solutions of
radial displacement in the plastic and viscoelastic zones are derived
respectively, and the superimposed combination forms the analytical solution of
displacement distribution in the surrounding rock. Following this, the radial
displacement and stress fields of the surrounding rock are analyzed as a
function of time, and the deformation law of the opening is described. The
applicability of model is verified with the help of FLAC3D and the theoretical
solution of related literature. On this basis, parametric sensitivity analysis
of longterm deformation is carried out. The results
show that the three most critical parameters in each phase are internal
friction angle, cohesion, and Young′s modulus, and the
creep parameter has significant sensitivity only in its control phase.
