Seismic Response and Damage of Ballasted Tracks: A Comparative Assessment of Unreinforced and Ballast-Glue-Reinforced Conditions

A 3D discrete element model was developed to investigate the seismic response of ballasted tracks and the reinforcement effect of surface-layer ballast glue. The model reproduced typical seismic damage features, including ballast shoulder degradation and slope collapse. After reinforcement, sleeper peak acceleration decreased by about 2%, ballast lateral displacement by about 10%, and vertical settlement by 20–48.4%. Ballast glue also mitigated the degradation of lateral ballast resistance by 10–17%. Moreover, the reinforced ballast bed showed a higher proportion of strong force chains, indicating improved load transfer and enhanced structural stability under seismic excitation.