Dynamic Simulation Analysis Of Train-Track-Bridge Coupling Of Long-Span Concrete Cable-Stayed Bridge

With the vigorous development of high-speed railways,China’s high-speed railway network is continuously extending to wider and more complex areas,and long-span bridges and ballastless track structures have been gradually promoted and applied.Therefore,clarifying the dynamic performance and interaction relationship of the train-track-bridge coupling system under the actual operating conditions has important reference significance for the design and application of ballastless track laying on large-span bridges.This paper selects the actual engineering as the research background,and takes the newly built Zheng-Ji high-speed railway Changqing Yellow River Bridge and the ballastless track structure on the bridge as the research object,considering the geometric deformation of the bridge-track system caused by temperature,the dynamic performance of the train-track-bridge coupling system when the train crosses the bridge at high speed is calculated and analyzed by using the ANSYS and UM co-simulation method.The main research contents are as follows:(1)Considering the role of bosses and isolation buffers,a refined finite element model of the bridge-track system including the main structure of the bridge,supports,track slabs,base slabs is established.The transfer characteristics of the bridge and the ballastless track structure on the bridge are compared,and the geometric deformation of the bridge-track system under the combined heating and cooling conditions is compared and calculated,and the long-wave irregularity data of the track under the most unfavorable conditions are obtained.The track short-wave irregularities are superimposed to obtain the track combination irregularity excitation.(2)The natural vibration characteristics of bridge and track are analyzed,and the flexible bodies of bridge and track sub-structures are obtained by reducing the degrees of freedom of sub-structures.An 8-car marshalling train vehicle model based on the CRH2 C EMU train is established and verified,and the appropriate wheel-rail contact relationship is set to realize the data exchange between the vehicle and the bridge-track system,and obtain a complete vehiclerail-bridge coupling system dynamic analysis model.(3)The influence of the geometric deformation of the bridge caused by the temperature change on the high-speed driving on the bridge is discussed.According to the relevant specifications,the evaluation index of the dynamic response of the vehicle and the bridge is proposed,and the dynamic response of the vehicle-bridge coupling system at different driving speeds is calculated.The comfort,safety and dynamic performance of the bridge are evaluated accordingly,which lays the foundation for the analysis of the dynamic performance of the ballastless track on the bridge later.(4)The vibration problem of the ballastless track on the bridge is studied.According to the unfavorable position of the dynamic response of the main girder and the evaluation index of the dynamic response of the ballastless track on the bridge in the calculation results in Chapter 4,the ballastless track on the bridge is explored when the train crosses the bridge at high speed.Vibration,deformation characteristics and transmission laws of structures.On this basis,the influences of the vertical stiffness of the fasteners and the supporting stiffness of the isolation buffer cushion on the dynamic performance of the bridge-track system are discussed,and according to the calculation results,the reasonable ratios of the vertical stiffness of the fasteners and the supporting stiffness of the isolation cushioning cushion are put forward.