Experimental investigation on hydrodynamic performance of submerged floating tunnel under the protection of a new floating energy dissipation and anti-vibration device

This study describes an efficient and applicable approach to decrease the hydrodynamic response of a submerged floating tunnel (SFT). A new type of floating energy dissipation and anti-vibration device is proposed, mainly consisting of a floating box superstructure with water and a polyvinyl chloride porous media substructure. The experimental model of an SFT with the present protection device is designed and conducted in a wave-current flume. The wave-current attenuation mechanisms for the present protection device are experimentally investigated. The sensitivity analysis for the key parameters, e.g., structure type and wave-current parameter, is conducted to investigate the hydrodynamic performance of the SFT with the present protection device. The results show that the present protection device has excellent wave-current attenuation capacity, and the transmission coefficients and the current-velocity attenuation coefficient reach 0.2 and 0.15, respectively. The sway, heave, roll, and typical cable tension from the SFT with the protection are, respectively, about 8, 6, 8, and 3 times smaller than that from without the protection. The results show that the SFT with the present protection device has excellent anti-vibration performance, which is beneficial for its safety and stability. This study has important theoretical and practical values to the anti-vibration design of SFTs serviced in complicated ocean environments.