Research On Coupled Vibration Of High-Speed Train-Cable-Stayed Bridge Under Earthquake And Wave

With the rapid development of high-speed railway in China,the high-speed railway network began to extend to the southeast coastal areas.The southeast coastal area of China is adjacent to the seismic zone,with frequent seismic activities,complex sea conditions and strong tides.More and more high-speed rail lines need to cross seismic zones and straits.Steel truss cable-stayed bridge has become the first choice for sea crossing bridges because of its excellent span capacity and stiffness.The dense high-speed railway network and the bridges with high proportion and long span together determine that the high-speed trains will inevitably run on the bridges under the action of earthquake and wave.Earthquake,extreme wave load and hydrodynamic pressure caused by earthquake have become one of the main factors threatening the health and safety of sea crossing cable-stayed bridges and the running safety of high-speed trains.Therefore,based on CFD method and multi-body dynamics simulation technology,this paper takes Pingtan Strait Bridge Yuanhong channel bridge and CRH3 high-speed train as the research objects,uses numerical simulation method to calculate the wave load of the foundation structure of Pingtan Strait Bridge Yuanhong channel bridge,selects the measured seismic wave data,and considers a variety of factors,The multi-body dynamic coupling simulation model of high-speed train-cable-stayed bridge under the combined action of earthquake and wave is established.The effects of earthquake,wave load and their combined action on the dynamic characteristics of Yuanhong channel bridge and the train operation on the bridge are analyzed in detail.The effects of vehicle speed,wave passage effect and load phase difference are studied.The main research contents include:(1)Based on the CFD method,a three-dimensional numerical flume is established.By comparing with the theoretical results,the reliability of the regular wave generated by the numerical simulation method in this paper is verified;By comparing with the experimental results,the reliability of the numerical simulation method for calculating wave loads on structures of different scales is verified.According to the actual engineering background,the wave loads of the composite foundation under Pingtan Strait Bridge Yuanhong channel bridge in different return periods are calculated by using the numerical simulation method in this paper.(2)Using the multi-body dynamics software SIMPACK,the refined dynamics model of CRH3 Multiple Units considering multiple degrees of freedom and nonlinear factors is established;The finite element model of Pingtan Strait Bridge Yuanhong channel bridge is established by using the finite element software ANSYS,and the substructure is reduced.The flexible bridge model is entered into SIMPACK.The vehicle bridge coupling system is established by using the dummy element method.(3)According to the characteristics of the bridge site,three different types of measured seismic waves are selected.The large mass method is used to input the earthquake as the external excitation into the vehicle bridge system.The non-uniform excitation is used,and the wave passage effect is considered along the longitudinal direction of the bridge;The M method is used to calculate the soil spring stiffness,and the spring force element is used to consider the pile-soil interaction of the bridge foundation;The additional mass of seismic hydrodynamic pressure on the composite foundation is calculated by using the rigid column method,and the additional mass of hydrodynamic pressure is applied on the foundation through the mass unit.(4)According to the established high-speed train cable-stayed bridge coupling vibration model,the dynamic response characteristics of the train bridge coupling system without external load,the dynamic response of the train bridge system under the independent action of earthquake and wave load,and the dynamic response results of the train and Bridge under the combined action of earthquake and wave are analyzed respectively,and the different effects of earthquake and wave on the train bridge system are analyzed;The influence of train speed,wave passage effect and the phase of earthquake and wave load on the train bridge system is studied,and the threshold of train speed under the combined action of earthquake and wave is proposed.