穿越城区连拱隧道合理施工工法研究

以重庆市沙坪坝区的站西站东路下穿道工程为依托,深入研究穿越城区连拱隧道的合理施工工法,从沉降、结构、施工、经济性等方面对比台阶法和CD法,并优化CD法的施工工序,确定对沉降变形起控制作用的施工关键工序。结果表明:修建穿越城区的连拱隧道,采用CD法引起的拱顶及地表沉降量、支护结构承受的最大拉压应力及围岩坍塌范围较台阶法大幅减少;优化后的CD法在控制沉降、结构受力、施工组织方面具有综合优势,其在施工中对地表及拱顶沉降起控制作用的关键工序对相应部位的拱顶及地表累计沉降的影响比重均达到10%以上。

Study on Reasonable Construction Method for Arch Tunnel through Urban Area

Based on the underpass project of the west to east road in Shapingba District of Chongqing City,the paper studies intensively the reasonable construction method of double-arch tunnel through the city.The Beach method and CD method are compared in terms of settlement,structure,construction,economical efficiency and so on,and the later method is optimized and key construction processes for controlling settlement are determined.The results of this study show that:for the construction of doublearch tunnel through the city,the vault settlement and surface subsidence,the maximum tensile stress of the supporting structure and the surrounding rock damage range caused by the CD method are reduced substantially compared with those caused by Beach method;the optimized CD method is superior in terms of settlement control,structure bearing capacity and construction organization,and the effect of key construction processes for controlling vault settlement and surface subsidence is more than 10% on the accumulated settlement of corresponding parts.