Abstract: Currently, Zhanjiang bay tunnel is the deepest cross-sea shield tunnel in China. The tunnel segments are connected by oblique bolts with staggered arrangements. In this study, the forces in the maximum covering soil section and the maximum water depth section were calculated by a modified usage method and a beam-spring method, respectively. Then the distribution pattern of water-earth pressure was analyzed by comparing theoretical results with measured results of segment stress and water-earth pressure. The analytical results show that both of the modified usage method and the beam-spring method can well simulate the stress state of tunnel segment. Especially, the results calculated by beam-spring method is relatively closer to measured results than those by the modified usage method. It is found that segments are in flattening states and the results obtained by beam-spring method are greatly affected by the position of capping blocks. Terzaghi’s relaxed earth pressure and the linear distribution of water-earth pressure are also applicable and safe for the deeply buried submarine tunnel. In this project, the lateral load of the segment is dominated by radial water pressure, which mainly affected the axial force. Therefore, this study can provide a useful reference for the design and construction of high-head cross-sea shield tunnel segments in the future.

Key words: beam-spring method, modified usage method, cross-sea shield tunnel, force analysis of segments, monitoring feedback