Study On Track Irregularity Power Spectral Density Of High-Speed Railway And Its Correlation With Vehicle Running Quality

Track irregularities represent the general geometrical state of track structure, it is an important embodiment of overall performance and bearing capacity of the railway track. Going through the leaping development of high-speed railway, Chinese high-speed railway has a large scale nowadays. But with short operation time and insufficient management experience, the essential feature of high-speed railway track irregularity and its correlation with vehicle running quality are not understood profoundly and subtly. The track irregularity management standard of high-speed railway is still in the trial stage which needs to be further improved. Against this background, aiming at high-speed railway, the study on track irregularity power spectral density(PSD) and its correlation with vehicle running quality is carried out in this paper.Firstly, combining the data preprocessing method, power spectral density estimation method and curve fitting method, the construction method of high-speed railway track irregularity PSD is studied systematically. The program of analyzing and constructing track irregularity PSD (TIPSDAC) for high-speed railway is compiled. On this basis, taking the measured track irregularity data of 250-350km/h and 200-250km/h high-speed railway as examples, the track irregularity PSDs of typical high-speed railway are obtained. The characteristics of the spectrum are analyzed and compared with some high-speed track irregularity spectrum at home and abroad.Secondly, based on vehicle-track coupled dynamics theory, the high-speed vehicle-track (slab and ballast track) coupled dynamics procedure, which is used for high-speed vehicle dynamic performance analysis, is compiled. The procedure is validated by the SIMPACK. software and field dynamic test data, its accuracy and reliability are explained.Then, using the high-speed vehicle-track coupled dynamics model, the influence of harmonic and stochastic track irregularity on the high-speed vehicle dynamic performance is analyzed. The type of track irregularity includes longitudinal level, alignment, crosslevel, gauge and twist. For the harmonic irregularity, the influence of the wavelength and amplitude of single and continuous harmonic waves on the dynamics indexes is analyzed. For the stochastic irregularity, the variation characteristics of the dynamics indexes in time and frequency domain are analyzed. In addition, the amplitude limits and its dynamics index controlling characteristics of the single harmonic irregularity are calculated and analyzed in the 250-400 speed range and 1～200m wavelength range. According to the above results, the sensitive wavelengths of the single and continuous harmonic irregularity, which have stronger influence on the vehicle running quality, are extracted.At last, the Chinese high-speed track irregularity management standard is compared with the management standard abroad, the differences are obtained. On this basis, a method for estimation of track irregularity limits using track irregularity PSD of high-speed railway is presented. Taking the Chinese high-speed ballastless track irregularity PSD as the input, the track irregularity amplitude limits are estimated, when a typical high-speed vehicle running on the slab track in the 250～400km/h speed range. The estimated limits are compared with the limits calculated under the excitation of the 10m and 40m wavelength single harmonic waves, and with the high-speed track irregularity standards of different countries. Based on the estimation method, the limits of track irregularity PSD are also studied and the track irregularity PSD limits under 250-400km/h speed domain are presented. The approach to evaluate track irregularity state using the presented track irregularity PSD limits is explained. Synthesizing the above analysis, suggestions are proposed to further improve the track irregularity management standard of Chinese high-speed railway.