Abstract Summary
The issue of the environmental vibration caused by subway trains has become a hot topic in both academic and engineering communities. An accurate train-track-tunnel-soil interaction model plays a decisive role in the prediction of subway train-induced environmental vibration, which is conducive to engineering design and construction. To this end, a comprehensive train-track-tunnel-soil coupled dynamics model is proposed in this study by combining the train-track sub-model and the tunnel-soil sub-model, in which the lining and grouting zone of the shield tunnel are regarded as cylindrical composite shells, and the soil is simulated as a viscoelastic artificial boundary. In addition, based on Kirchohhff plate vibration theory and Mindlin plate vibration theory, the motion of track slab is formulated to provide a more accurate simulation. Then, the accuracy and reliability of the train-track-tunnel-soil system dynamic model are validated by comparing the results calculated by the model with the data obtained by the field test under the subway train operation. Finally, the train-track-tunnel-soil coupled dynamics model is used to analyze the influence of different track structures, including monolithic track and three kinds of floating slab tracks, on the vibration characteristics of tunnel-soil system induced by subway trains. Results show that the floating slab tracks have great vibration isolation performance compared with the monolithic track, but have an amplification effect for the vibration around 10 Hz. The dynamic stress fluctuation of the soil under the floating slab track is slighter than that under the monolithic track, which indicates that the usage of the floating slab track can alleviate the stress state of the soil under the cyclic dynamic loads of the moving trains.
