Experimental study on the dynamic responses of a segmental submerged floating tunnel model under the coupled action of waves currents, and earthquakes

Abstract

The submerged floating tunnel (SFT) is suspended in the ocean by gravity buoyancy and cable tensions, facing threats from various environmental loads, including wave-current interactions and earthquakes. This study examines the coupled effects of wave, current, and earthquake on a segmental SFT model with three cable layouts through hydrodynamic experiments, collecting displacement, cable forces, and flow field data. The results show that frequency-locking under unidirectional current and resonance under regular waves significantly amplify the dynamic response. The dynamic response under wave-current coupling is generally smaller than the sum of individual load responses. Seismic effects are influenced by the initial state, with multiple load coupling always amplifying the seismic response. Among the cable layouts, the double-tilted multi-cable configuration performs best under coupled multi-load conditions.