中央大道海河沉管隧道最终接头关键技术

天津市滨海新区中央大道海河隧道为北方首座内河沉管隧道，针对沉管隧道最终接头以及临水工程超深基坑围堰施工、止水与安全稳定性问题采取措施予以改进。沉管隧道的最终接头，采用干作法施工，在围堰结构安装定位、接头防水措施上以及水下混凝土模板设计等方面进行了技术改进，确保了最终接头以及沉管连接段27m深的小基坑施工质量安全。该工程所积累的实践经验，为我国今后沉管隧道工程以及类似临水工程设计与施工，提供了参考依据与经验指导。

Key Techniques for the Final Joints of the Immersed-Tube Tunnel of the Haihe River at the Central Avenue

The Haihe Tunnel at the Central Avenue of the Binhai New District of Tianjin City is the first tunnel underrunning an inland river in north China. Aiming at solving the problems of the final joints of the immersed-tube tunnel,the cofferdam construction of the super-deep foundation pit for the near-water project, stopping water, safety and stability, some necessary improvement measures are taken to ensure the successful completion of the construction. With the final joints of the immersed-tube tunnel, the construction is performed by the dry construction method. Technical innovation is also applied to the fixing and positioning construction of the cofferdam structure, the water-proof measures for the joints, the design of the underwater concrete forms,etc. ,all of which help ensure the security and quality of the final joints and the quality of the construction of the small 27-m-deep foundation pit for the connective section of the immersed tube. The experience obtained from this project provides reliable referential grounds and guidance for the design and construction of other immersed-tube tunnel projects and similar near-water projects in the future.