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High-speed trains (HSTs) induce vibrations that deteriorate the embankments of ballastless tracks, particularly in frozen regions, necessitating vibration assessments for existing high-speed railways (HSRs). This study developed an indirect thermal-dynamic coupled two-dimensional (2D) finite element (FE) model to investigate the dynamic responses of the embankment of ballastless tracks to various subgrades and subsoils, train speeds, and frost depths in frozen regions. The results indicate that subgrade is the key parameter to analysing the dynamic response of the train–track–ground system considering train speeds. A fast and high-accuracy prediction method for the vibration responses was developed using an artificial neural network (ANN) and used to predict the vibration level under different conditions. Prediction results determined train speeds under 400 km/h safe for HSRs. This study can improve knowledge of ballastless track substructure design and extend the applicability of the current railway code to higher train speed conditions in frozen regions. • Proposed an accurate and reliable artificial neural network-based prediction model. • Train speeds under 400 km/h are safe for high-speed railways in frozen regions. • Subgrade is key to analysing the dynamic response of train–track–ground systems. • Substructure layer reinforcement is recommended for higher speeds. [ABSTRACT FROM AUTHOR]

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. • Field test on embankment vibrations in unfrozen and frozen conditions due to China's high-speed trains are conducted. • Effects of seasonal variations and train speeds on time- and frequency-domain characteristics are analyzed. • The range on the dynamic impact coefficient in unfrozen and frozen conditions are compared. [ABSTRACT FROM AUTHOR]

Finite element (FE) simulations are increasingly providing a versatile environment for conducting dynamic response studies on the embankment induced by high-speed train (HST). In this environment, vibration mitigation strategies for the subgrade may be assessed to achieve economic and practical solutions. To investigate the vibration behaviors of embankment induced by HST in seasonally frozen regions, an FE modeling was developed and validated by the field test. The investigation noted significant differences in response features in different seasons. For the sake of providing useful engineering information relating to vibration mitigation, a parametric study was conducted to preliminarily investigate the effect of constructing a wave impeding barrier (WIB) at the site. The influences of the material modulus, the size and the embedded depth of WIB on the vibration mitigation were also systematically analyzed in the time domain and frequency domain and then discussed. It showed that the stiffening effect of the WIB led to a shift of response from a large one to a small one. The results convincingly indicated that the vibration mitigation effect of WIB would be improved when its modulus and size increased or the embedded depth decreased. And it also revealed that the WIB might amplify rather than reduce the ground vibration when its embedded depth was larger than a threshold value. Overall, the conducted study highlights the potency of vibration mitigation in seasonally frozen regions by installing a WIB in the subgrade. • The vibration behaviors of HST subgrade in seasonally frozen regions are simulated. • The vibration isolation effect of WIB used in seasonally frozen regions are investigated. • The effectiveness of WIB increases as its stiffness and size increase and decreases as its embedded depth increases. • The analyses indicate that improper design of WIB may amplify the vibration. [ABSTRACT FROM AUTHOR]