Keywords: train-ballasted track-subgrade system, multi-body dynamics, discrete element method, finite difference method, macro-microscale dynamic response, coupled modeling.

With the growing complexity of high-speed railway operations, the train-ballasted track-subgrade system is increasingly subjected to intensified dynamic loads and operational demands, posing significant challenges to structural integrity and maintenance strategies. However, most existing numerical models treat the train, track, ballast, and subgrade as decoupled subsystems, thereby failing to capture the essential dynamic interactions within this integrated system. To address this limitation, this study proposes and develops a coupled multi-scale dynamic simulation framework that integrates a Multi-Body Dynamics (MBD) model for the train, a Discrete Element Method (DEM) model for ballast particles, and a Finite Difference Method (FDM) model for the continuous subgrade. This framework enables a comprehensive investigation of both macro- and micro-scale dynamic responses under varying train speeds ranging from 250 to 350 km/h. The results show that the vertical acceleration of the train body increases by 25% as speed rises, while lateral acceleration and wheel-rail contact forces increase by 85.9% and 54.7%, respectively. Speed-dependent precursor displacements are observed in the rail and sleeper, and ballast deformation at 350 km/h increases by 144% compared to that at 250 km/h. At the granular scale, the proportion of sliding contacts among ballast particles increases by 64% when train speed exceeds 325 km/h, the force chain network becomes more dispersed, and up to 73% of the sleeper base load is carried by force chains. These findings suggest that 325 km/h may serve as a critical threshold for ballast maintenance, indicating the need for enhanced monitoring and more frequent ballast replenishment in key zones. The multi-scale modeling strategy proposed herein offers novel theoretical insights and methodological guidance for dynamic analysis and intelligent maintenance of high-speed railway infrastructure.

download the full-text of this paper (PDF, 1583 Kb)

go to the previous paper
go to the next paper
return to the table of contents
return to the volume description