Study On The Influencing Factors And Evaluation Methods Of The Track Vertical Profile Irregularity On The High-speed Railway Bridge

The track irregularity is the main excitation source of vehicle system and line structure vibration.The high-speed railway puts forward strict requirements for the track smoothness.The bridge is widely used to replace the traditional Subgrade in the high-speed railway in China,and the operation practice has proved that the track irregularity closely related to the structural characteristics will be formed in the bridge section,while the current research on the track irregularity on the bridge is less.In this paper,the structure of ballastless track on the CRTSII type bridge is established by the finite element analysis software,and the CRH2 motor car and flexible track models are established by the multi-body dynamics software.Finally,the vehicle rail bridge coupling dynamics analysis model is established.Secondly,it analyzes the influence of different bridge structures(simple supported beam bridge,continuous beam bridge),key parameters of track structure(fastener system stiffness,support stiffness,bridge structure damping,bridge structure size),driving speed on the vibration response of vehicle rail bridge coupling system,and calculates the factors that have great influence on vehicle rail bridge coupling vibration;it also analyzes bridge structure parameters,track structure parameters and vehicle rail bridge coupling vibration The influence of vehicle running speed on the dynamic high and low irregularity of the track on the bridge is summarized.Finally,through the vibration response of the coupling system of the track height irregularity on the bridge and the vehicle rail bridge,the wavelength weight curve of the track height irregularity on the bridge is calculated;according to the spatial frequency range of the wavelength weight curve,the track irregularity on the bridge is divided into N frequency band waveform components,the standard deviation of the track irregularity data in each frequency band is calculated and the weight coefficient is given,and finally the sum is obtained on the bridge Weighted quality index of track height irregularity(b-twqi).By comparing the correlation between the b-twqi,the standard deviation of track irregularity samples and the vibration response of the coupling system,it is found that the b-twqi is better.It is applied to the track inspection data of a 2.2km long Multi Span Simply Supported Beam Bridge of Beijing Shanghai high speed railway,and the weighted mass index of track is calculated.The results show that:(1)Through the comparative analysis of the vibration response of different bridge structures,track structural parameters(fastener system stiffness,support stiffness,structural damping,structural size)and driving speed to the vehicle rail bridge coupling system,it is found that: the vibration response of different bridge structures is significantly different;the bearing stiffness and structural damping have a greater impact on the vibration response of the vehicle rail bridge coupling system;the vibration of the vehicle rail bridge coupling system The dynamic response increases with the increase of driving speed.(2)The dynamic height irregularity in the middle of continuous beam bridge is greater than that in the middle of simply supported beam bridge.(3)From the angle of amplitude,the influence of track structure parameters on the dynamic irregularity of track on the bridge is small,but from the angle of track spectrum,it can be seen that in the sensitive wavelength range,the dynamic irregularity of track on the bridge changes obviously with the track structure parameters.Therefore,in the analysis of the influence of track structure parameters on the track dynamic irregularities on the bridge,the influence of different wavelength components and intervals should be considered.(4)When the driving speed is in the range of 80-200 km / h,the dynamic height irregularity of the track on the bridge increases with the increase of the driving speed.(5)The B-TWQI has a higher correlation with the vibration response of the coupling system,which is better than the TQI.