Distribution mode of seismic residual track irregularity for high-speed railway

As a significant lifeblood during earthquake mitigation and post-earthquake reconstruction, railway transportation undertakes crucial tasks. Research on track irregularity induced by earthquakes lays the foundation for driving safety after earthquakes. A total of eighty arbitrary seismic records were chosen, and the distribution mode of seismic residual alignment irregularity was summarized. The differences in vehicle vibration under different distribution modes were analyzed. A target seismic residual track irregularity based on the distribution mode analysis was proposed, and the driving speed threshold after earthquakes was calculated. The research results show that under the action of transverse earthquakes, rails suffer an obvious alignment irregularity, that the amplitude of vertical irregularity is small, and that the distribution mode of alignment irregularity can be divided into unimodal and bimodal irregularities. Both the maximum amplitude of bimodal irregularity and the generated vehicle response are significantly smaller than those corresponding to unimodal irregularity. The latter could be simulated by the product of amplitude of track alignment during earthquakes, attenuation coefficient, shape correction coefficient and sine function. When the peak acceleration of transverse earthquakes is less than 0.25g, there is no need for the vehicle to slow down, whereas when it is larger than 0.25g, the vehicle needs to slow down moderately to meet the comfort requirements.