The Dynamic Responses Of The Submerged Floating Tunnel Under Seismic Effect

Submerged floating tunnel fixed by tension legs was simplified as the superposition of elastic beam and elastic support stiffness beam for the first time in this paper, its mechanical properties was reflected more really. The equation of motion of the floating tunnel pipe based on the Euler beam theory when forced vibration was presented, then linearized the nonlinear term of dynamic equations equivalently. Inputting the pseudo excitation to simulate random seismic and researching the response of submerged floating tunnel pipe. Besides, further research the dynamic response of the SFT under the P wave based on theory of beam on elastic foundation. The numerical simulation analysis indicated that the response of the pipe is reduced with the increasing of damping coefficient and tension leg spring coefficient, and the influence of the spring stiffness is more significant. Under the effect of the observed seismic force, the dynamic response of the tunnel weaken with the growing of K, and the timing of the peak of midspan displacement backwards gradually. So it is concluded that the stiffness of anchorage system is the key to SFT design, and the scope of stiffness design parameters is given.