Dynamic response analysis of submerged floating tunnel under impact-vehicle load action

Abstract

To invest the dynamic response of submerged floating tunnel (SFT) under shock-vehicle load action, this paper develops a SFT math model considering the coupled vibration of the vehicle, tether, and the flexible boundary tube by the Lagrange equation. The four-order Runge-Kutta method is used to solve the vibration differential equations. The model reliability is verified by using the existing theoretical model. The influence law of the tube end stiffness, impact load, vehicle load on the SFT dynamic response is discussed by combine with the data of the proposed SFT. The result show: Compared to existing theoretical models, the coupled SFT model can consider different boundary conditions of tunnel tube and reflect the tube dynamic response more accurately. The system's displacement significantly decreases with the tube end stiffness increase, but the effect is no longer apparent when it decreases to a specific value; The tension ratio between the mid-span tether and the edge tether increases significantly with the tube end stiffness increase. The system's displacement increases significantly with the impact momentum increases, and the vehicle's displacement increment is larger than the tube. The system's displacement increases linearly as the vehicle mass increase; The vehicle speed has a slight effect on the tube displacement, but it has a nonlinear effect on vehicle displacement.