Prototype tests on effective bending rigidity ratios of segmental lining structure for shield tunnel with large cross-section

Through the analysis of the sensitive factors of effective bending rigidity ratios of shield tunnel structure, an efficient solution method based on prototype tests is proposed for the effective bending rigidity ratios. The prototype tests on segmental lining structure of Nanjing Yangtze River Shield Tunnel and Guangzhou Zhujiang River Shiziyang Shield Tunnel are carried out. The variation of and with load conditions is deduced. The results show that under the same load conditions, when the profile is larger, becomes smaller, and meanwhile becomes larger. The value of of staggered assembling structure is larger than that of straight assembling structure. The values of vary in positive and negative bending regions, and the relationship between and becomes various when using different structural types. Furthermore, the relationship between and of the two different structural types is given, and the recommended values of and of segmental lining structure using the straight assembling and the staggered assembling are proposed for 10 m and 15 m class u nderwater shield tunnels .