Research On Track Irregularity Spectrum Based On Track Inspection Data Of Heavy Haul Railway

With the development of heavy haul railway in China,the traction quality,axle load and traffic volume of heavy haul trains are constantly improving,which aggravates the deterioration of heavy haul railway track geometry,and puts forward higher requirements for the smoothness of heavy haul railway track.As one of the evaluation indexes of track smoothness,track irregularity spectrum can reflect both the amplitude and wavelength characteristics of track irregularity and provide important basis for track maintenance.Although several expressions of track irregularity spectrum have been proposed for existing railways and high-speed railways in China,the research on track irregularity spectrum of heavy haul railway is still lacking and there is no standard for track irregularity spectrum of heavy haul railway.Consequently,the research on track irregularity spectrum of heavy haul railway is an urgent and important topic.Therefore,based on the research experience of highspeed railway track irregularity spectrum and the characteristics of track irregularity data of heavy haul railway,the research on track irregularity characteristics and spectrum of heavy haul railway are carried out in this thesis.Firstly,the classification and description method of track irregularity,the preprocessing method of track irregularity data and the estimation method of track irregularity are introduced in this thesis.Based on the all-year track inspection data of heavy haul railway,the variation law and the recommended management value of TQI are analyzed.The digital characteristics of track irregularity data are analyzed and the distribution of track irregularity amplitude of heavy haul railway is mastered.Secondly,the parameters related to the calculation of track irregularity spectrum of heavy haul railway are determined.Power spectrum calculation is carried out on track vertical,lateral,gauge and level irregularity data of heavy haul railway in January,May and September 2018 by Welch method,and the track irregularity spectrum of heavy haul railway and its evolution law with time are obtained.Then,the spectrum lines of January,May and September 2018 are preprocessed,and Levenberg-Marquart is used to fit the vertical,lateral,gauge and level track spectrum of heavy haul railway in January,May and September,and the geometric expression of track irregularity power spectrum density function of heavy haul railway is obtained.At the same time,track irregularity spectrums of heavy haul railway under different track geometry states are obtained by using the track irregularity spectrum density under different spatial frequencies obeying the chi-square distribution of degree of freedom 2.Finally,taking track vertical profile irregularity as an example,the obtained spectral density function of track irregularity is converted into time domain by inverse Fourier transform method and compared with the measured samples to verify the accuracy of fitting.Based on the multi-body dynamics software UM,the truck-track coupled model is established,and spatial samples are retrieved from the irregularity spectrum with accumulated frequencies of 0.2,0.632 and 0.90 by inverse Fourier transform method.Taking the spatial samples as the excitation of wheel rail system,the dynamic response law of truck under different running speed and different track geometry states are analyzed,which provide a theoretical reference for the application of track irregularity spectrum of heavy haul railway under different track geometry states.