Study On Train-bridge Coupling System Under Seismic Effect

Railway transportation is playing a mainstay role in the field of transportation in China.The recent advent in the new era of socialism with Chinese characteristics,the railway industry will be the first power of transportation.Due to the rapid development of social economy and the improvement of people's living standard,people ask for the more convenient and faster travelling,then the high-speed railway appear.However,due to variety of reasons,such as environmental protection,saving more space,post-construction settlement and so on,bridge's proportion in high-speed railway increased year by year.There is,in addition,because of the frequency and magnitude of earthquake increase these years,traffic safety is facing big challenges.Studying on Train-Bridge Coupling System under Seismic Effect has more value,which is beneficial to the earlier establishment of China's railway alarm and emergency disposal system,the system will escort people's life and fortune.The paper based on the finite element software Midas-civil and multi-body software Simpack2018,which simulated the working conditions of CRH2 passenger train running on the 10-span-32 m simply supported box girder bridge.The dynamic response of the bridge and the train is calculated respectively,and the safety evaluation is given according to the corresponding specifications.Finally,the paper gives out the safety threshold of train under seismic effect,and some views about Chinese railway warning and emergency disposal system had been proposed.Among them,the main conclusions are as follows:(1)The free vibration characteristic analysis of the train-bridge coupling system.The trainbridge coupling model's natural frequency of vibration is smaller than the single bridge model,it shows that the train-bridge coupling model is weaker than the single bridge model.Whether the single bridge model or the train-bridge coupling model,the increase of pier height will reduce the natural frequency of the structure.For the reason that the increase of pier height will reduce the stiffness of the bridge system.(2)The dynamic response analysis of the train-bridge coupling system under Seismic effect.There are 8 kinds of seismic waves are selected and used to put into the model,we find that the structure of 32 m railway box girder bridge has obvious seismic scaling effect,in which the lateral acceleration of seismic is magnified 2~3 times,the vertical acceleration magnified 1~2 times;The lateral acceleration of the dynamic response of the bridge is less than the vertical acceleration when the train running on the bridge,and the dynamic response of bridge of the train load is less than the seismic load;The increase of pier bridge will magnify seismic effect;China's 32 m railway box girder bridge has very high quality and reliability.(3)Analysing the train's safety under seismic effect.A model of train-rail-ballest bed is built based on Simpack,then the data from Midas-civil are puted in this model with considering the influence of the track irregularity.After calculating and analysing,the data show that the lateral force of wheel,derailment coefficient and wheel unloading rate can increase with the increasing of train speed.In addition,with the increasing of seismic intensity,these three safety index will increase,and the lateral force of wheel's threshold is most restricted.When the speed of train is more than 250km/h,these three safety index will grow faster then exceed safe limits.(4)The earthquake warning and emergency disposal system of Japanese railway is the most advanced.The development has experienced from S wave detection to P wave early warning,and finally developed into a comprehensive monitoring and alarm system.Due to being backward in this field,we should work harder.