Management Standard for Cyclic Irregularity of Ballastless Track Slab Based on Dynamic Short Chord

Based on the analysis of the geometric characteristics of the cyclic irregularity of slab ballastless track commonly used in high-speed railway in China, in view of the situation that single threshold is adopted to control track irregularity amplitude and short wave irregularity components such as cyclic irregularity is ignored in current management standard, the reasonable chord length is selected based on the transfer function of chord measurement method. The dynamic simulation model is established and verified. The influence of the measured value of cyclic irregularity chord on vehicle dynamic performance is analyzed. The management standard for the cyclic irregularity of track slab is proposed and verified by an example. Results show that the wavelength range of cyclic irregularity caused by track slab deformation is concentrated in 4~7 m. The dynamic track irregularity detection data re-output according to a certain chord length is in good agreement with the static chord measurement results, which can replace the static chord measurement and improve the field detection efficiency. The effective detection band of 5 m chord method is 3~10 m, which can cover the wavelength range of cyclic irregularity. Therefore, it is more reasonable to use 5 m chord for measurement. The four-level management standard for cyclic irregularity is based on 5 m chord vector. Under the speed level of 200~250 km • h-1, the values of grade I to IV are 5, 6, 9 and 12 mm respectively. Under the speed level of 250~350 km • h-1, those of grade I to IV are 3, 4, 6 and 9 mm respectively. According to the proposed management standard, the mileage of track slab deformation disease can be effectively identified. It can provide theoretical basis and guidance for the establishment of high-speed railway detection standards and field maintenance. © 2020, Editorial Department of China Railway Science. All right reserved.