Dynamic response of a track-subgrade system under moving train loads and non-uniform ground motions

In order to study the dynamic response of a track-subgrade system under the coupling effect of moving train loads and non-uniform ground motions, a three-dimensional refined finite element model was established, taking Beijing-Shanghai high-speed railway and CRH3 train as the research objects, and the dynamic response analysis of the track-subgrade system under earthquakes combined with moving loads was carried out. The non-stationary ground motion was synthesized by multiplying the stationary ground motion time history by the envelope function. The effects of train operating speed, axle weight and magnitude of non-uniform ground shaking on the dynamic response of the track-subgrade system were analysed parametrically. The results show that the response magnitude of the track-subgrade system does not increase with the increase of train speed, and there is a range including the critical speed in which the stronger vibration of the track-subgrade system will occur under the coupling of moving train loads and non-uniform ground motions. With the increase of train axle load or the PGA of ground motion, the track-subgrade system shows a more significant vibration response. Compared with uniform excitation, the maximum vertical displacement and the maximum vertical acceleration of the track slab appear earlier under non-uniform excitation. © 2024 Chinese Vibration Engineering Society. All rights reserved.