特大断面隧道支护结构现场试验与三维效应分析

In-situ test and 3D-effect analysis of a tunnel lining structure of large cross section

与普通公路隧道相比,双洞八车道特大断面隧道的结构受力更加复杂、施工方法更为多样化。结合目前国内规模最大的四车道特大断面隧道,对特大断面隧道进行现场试验,并基于现场试验结果,详细地分析特大断面隧道双侧壁导洞法开挖引起支护结构变形及受力的三维效应。研究结果表明：在特大断面隧道施工过程中,左导洞下台阶和核心土上台阶开挖对支护结构受力及变形影响较大,是支护稳定性控制的主要工序;特大断面隧道开挖的纵向影响距离大致为1~1.5倍导洞跨度,约为8~12m。研究成果可为日后类似工程的设计、施工和研究提供有益的借鉴和参考。

The mechanical behaviors of twin tube large cross-section tunnels with a total of eight traffic lanes are complex,and the construction methods diverse.In-situ test of the lining structure was conducted for the largest cross-section four-lane highway tunnel in China,and the 3D-effect of the deformation and stress of the lining structure constructed using the double-side-drift method was analyzed.The results indicated that during the construction,the excavation of the lower bench in the left drift and the bench in the core rock significantly affected the deformation and stress of the support structure.The longitudinal range of influence of the excavation of the tunnel is about 1 to 1.5 times of the drift span,from 8 to 12 m ahead of the work face.