Analysis of the interaction between bolt-reinforced rock and surface support in tunnels based on convergence-confinement method  

作　　者：Zhenyu Sun Dingli Zhang Qian Fang Yanjuan Hou Nanqi Huangfu 

机构地区：[1]Key Laboratory for Urban Underground Engineering of Ministry of Education,Beijing Jiaotong University,Beijing,100044,China

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2024年第6期1936-1951,共16页岩石力学与岩土工程学报（英文版）

基　　金：funding support from the Fundamental Research Funds for the Central Universities(Grant No.2023JBZY024);the National Natural Science Foundation of China(Grant Nos.52208382 and 52278387).

摘　　要：To investigate the interaction of the bolt-reinforced rock and the surface support,an analytical model of the convergence-confinement type is proposed,considering the sequential installation of the fully grouted rockbolts and the surface support.The rock mass is assumed to be elastic-brittle-plastic material,obeying the linear Mohr-Coulomb criterion or the non-linear Hoek-Brown criterion.According to the strain states of the tunnel wall at bolt and surface support installation and the relative magnitude between the bolt length and the plastic depth during the whole process,six cases are categorized upon solving the problem.Each case is divided into three stages due to the different effects of the active rockbolts and the passive surface support.The fictitious pressure is introduced to quantify the threedimensional(3D)effect of the tunnel face,and thus,the actual physical location along the tunnel axis of the analytical section can be considered.By using the bolt-rock strain compatibility and the rocksurface support displacement compatibility conditions,the solutions of longitudinal tunnel displacement and the reaction pressure of surface support along the tunnel axis are obtained.The proposed analytical solutions are validated by a series of 3D numerical simulations.Extensive parametric studies are conducted to examine the effect of the typical parameters of rockbolts and surface support on the tunnel displacement and the reaction pressure of the surface support under different rock conditions.The results show that the rockbolts are more effective in controlling the tunnel displacement than the surface support,which should be installed as soon as possible with a suitable length.For tunnels excavated in weak rocks or with restricted displacement control requirements,the surface support should also be installed or closed timely with a certain stiffness.The proposed method provides a convenient alternative approach for the optimization of rockbolts and surface support at the preliminary stage of tunnel design.

关 键 词：Analytical model Longitudinal tunnel displacement Fictitious pressure Active rockbolts Surface support reaction pressure Tunnel design 

分 类 号：U455.7[建筑科学—桥梁与隧道工程]