沉管隧道岸上最终接头处二次围堰结构设计与应用——以襄阳市东西轴线道路工程鱼梁洲段项目为例

Design and Application of Secondary Cofferdam Structure at Onshore Final Joint of Immersed Tunnel:a Case Study of Yuliangzhou Section on East-West Axis Road Project in Xiangyang,China

针对临江轴线干坞沉管隧道岸上最终接头处高水头作用下坞门二次围堰结构复杂、止水难度大等技术难题,提出新型钢壳夹壁混凝土围堰挡水结构、管节底部“橡胶止水带+模袋混凝土+水下注浆”三重止水结构。采用有限元数值方法对围堰挡水结构的强度和变形进行模拟分析,并采用室内试验对橡胶止水带的压缩止水性能进行研究,同时对模袋混凝土的压浆工艺及止水可行性进行了现场试验,达到了二次围堰高效快速施工、安全稳定使用以及无渗无漏的止水效果。该技术成功应用于襄阳市东西轴线道路工程鱼梁洲段项目沉管隧道施工中。实践表明:新型钢壳夹壁混凝土围堰挡水结构可用作二次围堰挡水设计,三重止水结构可实现管节与基础传力板的间隙在100 mm内时的可靠止水。

The high water head at the onshore final joint of the immersed tunnel of the dry dock of the Yuliangzhou section on the East-West axis in Xiangyang,China has led to a complex secondary cofferdam structure of the dock door and a difficult water stop.To address these issues,a steel shell sandwich wall concrete cofferdam water-retaining structure and a triple waterproof structure at the bottom of the immersed tube(i.e.,rubber water stop+mold bag concrete+underwater grouting)are proposed.The strength and the deformation of the cofferdam retaining structure are simulated using the finite element method.The compression sealing performance of the rubber water stop is examined using the laboratory test method.The grouting technology and the water stop feasibility of mold bag concrete are also investigated.The adopted technologies guarantee high efficiency,rapid construction of the secondary cofferdam structure,and good waterstop effect.The successful application of the recommended technologies shows that a new structure of the steel shell sandwich wall concrete cofferdam can be used in a secondary cofferdam water-retaining design.Furthermore,the triple waterproof structure achieves a reliable waterstop effect when the clearance range between the immersed tube and the force transfer plate foundation is within 100 mm.