Abstract:The floating of shield tunnel assembled segment is always a technological problem in the shield tunnel construction. With the development of the shield tunneling technology and the requirements of the standard, the problems of assembling difficulties and waterproof hidden danger caused by the floating of segments increasingly influence the construction and operation, and directly affect the engineering quality. The segment floating is mainly caused by the complex factors of segments without the anti-floating capacity during the construction and excavation. The current research shows that there are many factors causing the floating of shield tunnel segments, such as geological and hydrological conditions, soil unloading, non-uniform mortar casting and shield gesture control. Taking Shanghai Metro Line 2 West Extension Shield Tunnel Project as the background, through the theoretical analysis on the segment floating, the quantitative relationship between the segment floating and the relevant factor is obtained, which provides the theoretical basis for eliminating the floating of shield tunnel segments during tunneling, ensuring the construction precision and improving the engineering quality.
