A simplified method for determining earthquake early warning thresholds in high speed railways

This study conducts an exploration of determining the earthquake early warning thresholds for high-speed railways. Through shaking table tests and the analysis of two-dimensional and three-dimensional numerical models, an innovative approach to deriving earthquake early warning thresholds has been proposed. Firstly, the accuracy of the two-dimensional vehicle-track numerical model was validated, by comparing with the results of shaking table tests. Secondly, this paper discusses the impact of track irregularities on the risk of train derailment, pointing out that under seismic action, the correlation between derailment risk and vehicle speed is limited, and is more related to track conditions. Furthermore, by analyzing the superimposed effects of track irregularities and seismic action, the derailment patterns of trains during earthquakes were revealed. Finally, combining the safety margin of derailment indicators and the principle of superposition effects, this paper uses six different seismic waves to calculate and analyze the two-dimensional vehicle-track model, providing the earthquake early warning threshold for high-speed railways. This method offers a new theoretical foundation and practical guidance for the design and implementation of high-speed railway earthquake early warning systems.