基于收敛约束原理的大断面黄土隧道围岩与初支稳定性分析

黄土特殊的工程性质决定了黄土隧道结构的受力复杂性．大断面黄土隧道由于开挖断面大，开挖方法一般采用台阶法或交叉中隔壁法（CRD）．因此，沿用传统的观测点布置方法进行测点布置和位移观测，存在一定的困难．收敛约束法应用方便，思路明确．用收敛约束法对隧道初期支护进行稳定性分析，不仅能正确地反映隧道施工中的各种力学现象和过程，还能弄清楚围岩与支护“相互作用”和“动态作用”的特点．本文基于收敛约束原理，结合现场实测数据，对兰渝高铁某大断面黄土隧道的围岩稳定性和初支的安全性进行评价．为隧道的后续施工．提供参考．

Stability analysis of surrounding rock and supports in largespan loess tunnel using the convergence-confinement method

The stress patterns of the loess tunnel are complex because of special engineering characteristic of loess. For the big excavation cross section, the CRD or bench method is often used under tunnel construction. The common methods of displacement monitor have some problems. The convergence- confinement method is a useful theoretical tool for stability analysis of rock mass on tunnel construc- tion. Although the method cannot accurately reflect mechanical characteristics and processes of the tunnel construction, the characteristic of interaction and dynamic effect between rock and support can be found out. Based on the field monitor data, this paper analyzed the stability of the surrounding rock and safety of initial support by convergence-confinement method. The results provide a reference for the following tunnel construction.