Deformation and Stress Analysis of Pile-Supported Immersed Tunnels under Seismic Loads

Abstract

The stress and deformation of pile-supported immersed tunnels under seismic loads is a critical issue in tunnel design. This paper utilizes ABAQUS (version 2020) finite element software to analyze the seismic load response of the sand compaction pile-immersed tunnel–seawater pressure (SIS) system, which is verified by a physical model. The study shows that the suppression effect of the seawater on the vertical frequency of the tunnel increases with depth. When the replacement rate of the piled foundation reaches 50%, the deformation of the tunnel “H-shaped” structures increases, which also changes the vertical frequency of the tunnel. However, the presence of the suppression effect causes resonance injury at the far end of the tunnel from the earthquake source, resulting in a shift of the peak stress point. It was also found that seawater pressure affects the resistance–deflection (p-y) at the tip of the pile more than at the end of the pile. The slenderness ratio (γ) of the pile affects the p-y value at the end of the pile more than at the tip of the pile. The connection between the piled foundation and the tunnel is most stable when γ is in the range of 9.25 to 15.