A review on the progress and feasibility of helical piles for immersed tube tunnels

This review investigates the potential feasibility of helical piles as foundation systems for immersed tube tunnels. Helical piles, characterized by their rapid installation, low environmental disturbance, and high axial and uplift capacity, offer a promising alternative to conventional pile foundations in deep marine environments. The study synthesizes recent advances in understanding helical pile behavior, including axial and lateral bearing mechanisms, settlement responses, torque–capacity correlations, and group interaction effects, with a focus on their applicability to the unique demands of immersed tube tunnel foundations. Comparative analyses of torque models in sand and clay, as well as the influence of structural parameters such as helix geometry, spacing, and end conditions, are presented. Despite remaining challenges in predicting load–displacement relationships, installation torque in marine strata, and large-scale constructability, helical piles demonstrate considerable potential for use in deep immersed tunnel foundations. The review concludes that, with further research and adaptation for underwater construction, helical piles could offer a more efficient, adaptable, and sustainable foundation solution for future immersed tube tunnel projects.