Study on vehicle-tunnel coupling vibration of submerged floating tunnels considering tube joint effects under wave action

As an innovative structure for deep-water transportation, submerged floating tunnels (SFT) demonstrate significant advantages in cross-sea engineering due to their ability to adapt to complex loads. Recent studies have highlighted the vehicle-tunnel coupled vibration under wave action as a key research focus. In previous studies on vehicle-tunnel coupled vibrations, models with uniform tube stiffness were commonly used, focusing mainly on the tunnel’s dynamic response, the vehicles’ dynamic response and ride comfort within the SFT have been largely overlooked. In view of the current research status, based on wave theory and vehicle-tunnel coupling analysis theory, a new method of SFT vehicle-tunnel coupling vibration analysis combined with pipe joint effect is proposed, the accuracy of the method is verified, and the following conclusions are drawn: (1) Under wave forces, the stiffness of tube joints has been found to significantly influence the dynamic response of SFT within a certain range; (2) Both the vehicle and the tube of the SFT exhibit low-frequency vibrations in wave environments, with horizontal responses being greater than vertical ones; the displacement, velocity, and acceleration of the tube show periodic fluctuations, and the vibration frequency aligns with the wave frequency; (3) When evaluating driving comfort, attention must be paid to low-frequency vibrations under 1 Hz, as they can potentially trigger motion sickness.