The Dynamic Responses of the of the Submerged Floating Tunnel under Seismic effect

Based on the theory of elastic foundation beam, dynamic equations of submerged floating tunnel(SFT) tube under seismic force are presented. For investigating the influence of P wave, tunnel length and stiffness of anchorage system on SFT tube, the nonlinear dynamic analysis method is applied. By regarding SFT as an elastic-plastic vibrating system and inputting seismic acceleration records, numerical simulation results are obtained. The research results indicate that with the increase of the spring stiffness, the response of the tube decreases under the effect of the observed seismic force and the peak value appearance time of mid-span displacement response put off gradually. Besides, the effect of tunnel length on the displacement response is limited when the spring stiffness value is fixed. As the key to SFT design, the scope of stiffness design parameters are given in this paper. The research would provide a reference for seismic design and further study of SFT.