RESEARCH ON THREE-DIMENSIONAL NONLINEAR COUPLED VIBRATION OF CABLE-TUBE IN SUBMERGED FLOATING TUNNEL UNDER VEHICLE MOVING LOAD

A dynamic model of a three-dimensional nonlinear cable-tube coupled system of submerged floating tunnel is establisheed to analyze the dynamic response of the submerged floating tunnel under moving vehicle loads. Using Hamilton's principle, the three-dimensional motion equations of nonlinear anchor cables and tube are derived. Taking into account the spatial displacement coordination relationship between the cables and the tube, the Galerkin method is used for multimodal truncation to obtain the three-dimensional nonlinear coupled motion equation of cable-tube system in generalized coordinates. The vehicle is simplified as a uniformly moving concentrated load with equal space, and the lateral displacement and torsion of the tube caused by eccentric loads are considered. The fourth order Runge Kutta method is used for numerical solution to analyze the nonlinear dynamic behavior of the suspended tunnel under vehicle moving loads, as well as the influence of control system structural design parameters on the dynamic response of the submerged floating tunnel. The research results indicate that accurate numerical simulation can be obtained using multimodal calculations, compared with single mode calculations. By adjusting structural design parameters such as load eccentricity, buoyancy-weight ratio of tube, weight and speed of vehicle, the structural dynamic response of the system can be changed. The research can provide a basis for the structural design of submerged floating tunnel.