Earthquake response of the train-slab ballastless track-subgrade system: A shaking table test study

Earthquake is one of the major factors that provoke train derailment. To investigate dynamic responses of the train-slab ballastless track-subgrade system and derailment features of the train subjected to earthquake, a first large-scale shaking table test on this system was carried out in China. The loaded seismic wave is an earthquake wave of Zhengzhou Yellow River Bridge Site provided by the China Earthquake Administration. It was observed that the elevation of subgrade and embankment could magnify acceleration responses, and the transverse amplification effect of the elevation in soil was more pronounced than the vertical amplification effect. The acceleration response of a track slab was weaker than that of the top subgrade because of integrality and rigidity of the track slab. The bogie shows a shock-absorbing effect in the transverse direction. When the input amplitude was not larger than 0.14 g, the transverse and the vertical acceleration of the rail increased with rising earthquake amplitudes and fluctuated later. Meanwhile, the current stopping threshold for trains is conservative because the derailment factor was less than 0.8 and the peak lateral displacement of wheels was much smaller than the cross-sectional size of the rail model under a 0.12 g earthquake excitation. The current stopping threshold in codes could be reasonable in view of limited quantity and limited types of loaded earthquake in the test. The critical derailment condition of trains was 0.23 g when the Zhengzhou Yellow River Bridge Site earthquake was loaded, and the displacement analysis showed that it would be a great danger for train safety.