Deformation rule and mechanical characteristic analysis of subsea tunnel crossing weathered trough

Abstract

It is difficult to comprehend the deformation rule and mechanical characteristics in the construction process of subsea tunnel crossing weathered trough owing to the complex tunnel structure and unfavorable geological conditions. In this study, a geomechanical model test and a numerical model system for the excavation of subsea tunnel were developed based on Haicang Subsea Tunnel to investigate the characteristics of the tunnel displacement, stress, and seepage. After subsea tunnel excavation, the displacement, stress, and hydraulic pressure distribution of surrounding rocks were similar, with the release of stress and lower hydraulic pressure often accompanied with the growth of its displacement. Generally, multiple-physical monitoring information was interactional. In addition, the influence of seawater on the weathering trough was mainly concentrated in an area approximately twice the diameter of the hole, and the influence of water on the vault was greater than that of the sidewall. These results could serve as reference for the construction of subsea tunnel crossings and warning mechanisms of weathered trough.