Evaluation of structural bearing capacity of super‐large diameter submarine shield tunnels: A comparison between traditional segmental linings and double‐layer linings

Abstract Submarine shield tunnels are vulnerable to the influence of an external complex environment during operation, resulting in structural deformation overrun, joint leakage, structural crack damage, and other diseases. Given this, taking the Jintang Subsea Tunnel as the engineering background, a three‐dimensional elastic–plastic damage calculation model of the single‐layer and double‐layer lining structure of the shield tunnel was established, in which the mechanical effect of bond damage between segments and secondary linings was considered. Then, from the perspective of the safety bearing capacity of segments and joints, the bearing performance evaluation of the structure based on the N – M curve was carried out. Finally, five safety indexes were selected to analyze the deformation and failure characteristics of lining structures and clarify the safety state of the shield tunnel. The results show that the most dangerous parts of the lining structure are located at the tunnel haunch and vault. The vault and arch bottom of the secondary lining show a small eccentric tension state, and the haunch of the secondary lining shows a small eccentric compression state. By contrast, the lateral stiffness and ultimate bearing capacity of the double‐layer lining structure are increased by 46.5% and 43.1%, respectively. The stiffness coefficient of the foundation exerts the most pronounced impact on the safety control indices of shield tunnels. In contrast, the strength of interfacial bonds has a negligible influence on the governing of safety indices.