超大断面装配式明挖隧道结构及其施工方法研究

为提高隧道工程建设质量，针对国内明挖隧道装配式结构发展不成熟问题，以新森大道隧道为依托对超大断面明挖隧道装配式结构体系及施工方法展开研究，同时建立适用于公路、市政超大断面隧道装配式明挖结构体系，即“全预制”“仰拱现浇+上部预制”，并提出结构构造厚度建议值及多道防水构造方案。通过分析总结和数值模拟得出： 1）“仰拱现浇+上部预制”4分割方案在回填工序下的结构力学响应动态分析结果表明，该分割方案在施工过程中，结构应力、位移以及连接部位接头的张开角等均满足规范要求，且具备一定安全储备； 2）结合依托工程，提出一种适应于超大断面明挖隧道装配式结构的“边墙安装—仰拱现浇—拱顶拼装—细部作业—覆土回填”的施工方法及步骤。

Prefabricated Structure of Super Large Cross Section Open Cut Tunnel andIts Construction Method

The prefabricated structure construction technology of open cut tunnels is not mature in China. Thus, the prefabricated structural system and construction methods of a super large cross section open cut tunnel on Xinsen avenue in Chongqing, China, are being studied to improve the construction quality of tunnel projects. Then, a prefabricated structural system that integrates full prefabrication, cast in place invert, and prefabricated upper structure suitable for open cut highway and municipal large cross section tunnels is established, and the suggested structure thickness and multilayer waterproof structure scheme are proposed. The analytical and numerical simulation findings reveal the following: (1) The structural mechanical response analysis results of the four segmentation scheme in cast in place invert and prefabricated upper structures show that the structural stress, displacement, and opening angle of the joints meet relevant requirements and have a certain safety reserve. (2) A prefabricated open cut tunnel construction method with a super large cross section, i.e., sidewall installation, cast in place invert, assemble crown, detailed operation, and soil backfilling, is provided.