Field investigation into the vibration characteristics at the embankment of ballastless tracks induced by high-speed trains in frozen regions

摘要

Rapid growth and implementation of high-speed trains (HSTs) have made commuting easier. However, the vibrations induced by HSTs deteriorate the embankment of ballastless tracks, particularly of those constructed in frozen regions. In this study, a series of field tests are conducted on the Harbin-Dalian high-speed railway in frozen regions to investigate the vertical acceleration (A(z)) at the embankment in terms of the train speed (v) and distance from the track centreline (d). The characteristics of A(z) in the time and frequency domains are analysed based on the field test results. The results show that A(z) under the unfrozen condition is greater than that in the frozen condition. The periodic excitation of the HSTs can be identified from the time histories of A(z) within the range of 13.2 m from the track centreline. Moreover, the frequencies of A(z) can be characterized by v and geometrical characteristics of the train, regardless of seasonal variations. The peak vertical acceleration (A(p,z)) and frequency-weighted vertical acceleration level (L-az) are investigated with respect to v and d. In the unfrozen and frozen conditions, A(p,z )and L-az decrease in the form of a power function with increasing d. The higher the v value, the higher the A(p,z) value. The dynamic impact coefficient of embankment is introduced to identify the A(z) performance. Some useful recommendations are provided, and the results can be used for validating numerical predictions related to HST-induced vibration.