隐式中墙连拱隧道平行中隔壁工法设计与分析

Design and Analysis of Parallel Temporary Middle Wall Method for Double-arch Tunnel with Concealed Center Wall

分析连拱隧道工法研究现状和趋势,结合隐式中墙复合式连拱隧道[1-2]结构形式,提出一种新的连拱隧道施工方法—平行中隔壁法,其无需中墙临时支护,预留岩体保护中墙,减小对环境的影响,大幅提高连拱隧道的施工效率,实现连拱隧道的快捷施工。对平行中隔壁法进行详细设计与分析,并对其进行数值模拟。结果表明:平行中隔壁法可保证隐式中墙复合式连拱隧道施工安全,各上台阶步序开挖和拆撑为控制竖向变形的关键工序,左洞拱腰与中墙连接处和左洞仰拱与中墙连接处是初期支护的安全控制点。

Based on the analysis of current construction method and trend of double-arch tunnel, this paper presents a new construction method for a double-arch tunnel with concealed center wall, namely parallel temporary middle wall method, in which no temporary support of middle wall is provided and rock protection middle wall is reserved to reduce the impact on the environment, greatly improve construction efficiency and achieves fast construction of double-arch tunnel. This method is put into design and analysis with numerical simulation. The results show that the parallel temporary middle wall method ensures construction safety of a double-arch tunnel with concealed center wall, and the upper step excavation and support removing are the key processes for vertical deformation control, and the junction of left hole arch waist and middle wall, and the junction of 1 left hole invert and middle wall are the key points to the safety of preliminary lining.