Research On The Influence Of Girder Vertical Rotation Angle And Dislocation Of Girder Of The Train Running Performance On High-speed Railway Bridge

With the expansion of high-speed railway network in China,the natural conditions faced by the line during service are more complicated.The additional deformation of track is caused by the typical vertical deformations such as vertical rotation angle and dislocation of girder,which will threaten the safety of train running on the bridge.In this paper,the mapping relationship between the vertical rotation angle of girder and the deformation of track is derived based on the principle of minimum potential energy.A train-track-bridge dynamic model is established.Taking the train running index as evaluation standard,the vertical rotation angle and dislocation threshold of girder of the high-speed railway simply supported girder-bridge system are proposed by using probability statistical analysis method,The main research contents are as follows :(1)Based on the principle of minimum potential energy,the analytical mapping formula of track deformation of CRTSII ballastless simply supported girder-bridge system considering the influence of track boundary is established.The validity of analytical model is verified by comparing with the finite element method,and the influence of key structural parameters on the track mapping deformation under the vertical rotation angle and the dislocation of girder is analyzed.The results show that the peak value and effective deformation range of track are positively correlated with the deformation amplitude of girder.As the vertical stiffness of fasteners,mortar layer and sliding layer increases,the effective deformation range of track decreases and the coordinated deformation between layers of the track-bridge system is more consistent.(2)According to the existing train-bridge coupling theory,the traintrack-bridge coupling dynamic model of high-speed railway is established based on the finite element software ANSYS and the commercial mathematical software MATLAB.The results are verified by comparing with the calculation results of TTBSIM classical examples.(3)The influence law of different vertical deformation modes of the girder on the train running performance index is discussed since the superposition of track deformation and initial irregularity based on the vertical rotation angle and the dislocation of girder are used as the excitation source of the system.The results show that the peak fluctuation of train running index time history curve is obvious under unilateral vertical rotation angle and dislocation of girder,and the fluctuation range of train running index time history curve is large under symmetrical vertical rotation angle.(4)The dispersion degree and distribution law of different train running index samples are discussed based on probability statistical analysis method and fully consider the randomness of initial track irregularity,and the vertical deformation threshold of girder with 95 %guarantee rate is proposed.The results show that the sample size of single indicator tends to be stable after reaching 30 groups and meets the normal distribution.The deformation thresholds of vertical unilateral angle,symmetrical angle,single dislocation and multiple dislocations of girder are 0.18 ‰ rad,1.79 ‰ rad,3.9 mm and3.5 mm,respectively.