DYNAMIC RESPONSE ANALYSIS OF SUBMERGED FLOATING TUNNELS TO COUPLED WAVE-SEISMIC ACTION

To investigate the dynamic response of submerged floating tunnels (SFT) subject to the coupled action of earthquakes and waves, the wave load and seismic load were calculated by the Stokes wave theory and trigonometric series method, and the tube-tether model of SFT under the wave-seismic action was established based on the D’ Alembert principle. Combined with a planned SFT project, the load parameters and the response of the SFT system were analyzed. The results show that the tube-tether model was in good agreement with the tether vibration model under the coupled action of earthquakes and waves. However, the latter could not consider the parameter vibration of the system. The earthquake direction had a significant influence on the response of the SFT system. Under the same peak ground acceleration (PGA), the response of the system to the horizontal earthquake action was greater than that to the vertical earthquake action, and the response of the tethers was greater than that of the tube. There was a certain relationship between the PGA and the response of the system. The maximum displacement of the system increased linearly with the increase of the PGA. Based on the seismic load, the response of the system was increased by considering the wave load. With the increase of the wave height and wavelength, the response of the system increased linearly. Waves of small periods (less than 10 s) were easy to cause resonance of the system.