Analytical prediction for time-dependent interaction of a circular tunnel excavated in strain-softening rock mass  

作　　者：Chen Xu Sheng Wang Caichu Xia 

机构地区：[1]Institute of Rock Mechanics,Ningbo University,Ningbo,315211,Zhejiang,China [2]Ningbo Key Laboratory of Energy Geostructure,Ningbo,315211,Zhejiang,China

出　　处：《Rock Mechanics Bulletin》2024年第3期53-68,共16页岩石力学通报（英文）

基　　金：supported by the National Natural Science Foundation of China(Grant No.52278402 and 42207176);Ningbo Public Welfare Research Program Project(Grant No.2023S100);Ningbo Natural Science Foundation(Grant No.2022J116).

摘　　要：Viscoelastic plastic solutions for tunnel excavation in strain-softening rock mass and tunnel-rock interaction are proposed based on the Mohr-Coulomb and the Generalized Zhang-Zhu(GZZ)strength criterion considering stress path.The solutions are verified by numerical simulations,results show that the theoretical solutions are close to the simulated data.The evolutions of rock stresses,strains,displacements and support pressure were investigated and the influences of residual strength parameter,support stiffness,support timing,initial support pressure and viscosity coefficient on the rock deformation and the support pressure are discussed by proposed solution.It is found that strain-softening results in large deformation and high support pressure,with stiffer support and a larger viscosity coefficient contributing to even greater support pressure.Ductile support is recommended at the first stage to release the energy and reduce the support pressure by allowing a relatively large deformation.The support pressure,especially the additional support pressure at the second stage will be much smaller if a higher initial support pressure is applied at the first stage.This can not only control the displacement rate of surrounding rock and improve the tunnel stability at the first stage by exerting sufficient support pressure immediately after tunnel excavation,but also greatly reduce the pressure acted on permanent support and improve the structure stability at the second stage.Therefore,to avoid the instability of support structure,ductile support,which could not only deform continuously but also provide sufficient high support pressure,is recommended at the first stage.

关 键 词：Time-dependent behavior GZZ strength criterion STRAIN-SOFTENING Tunnel-rock interaction Stress path 

分 类 号：U455[建筑科学—桥梁与隧道工程] U451.2[交通运输工程—道路与铁道工程]