Influence of ballast elastic modulus on the mechanical performance of ballasted tracks based on a numerical method

Existing studies indicate that the elastic modulus of ballast exhibits a certain degree of variability. However, the relationship between the elastic modulus of ballast and the mechanical responses of the track, particularly the influence mechanism of ballast’s elastic properties on the mechanical behavior of the track structure, remains insufficiently explored in a systematic and quantitative manner. This research gap limits the accurate prediction and optimization of ballasted track performance. To address the research gap, a numerical analysis model was established to systematically investigate the influence of different ballast elastic moduli on the mechanical properties of the ballast bed. The results demonstrate that increased ballast elastic modulus significantly enhances the lateral resistance and overall stiffness of the ballast bed. When the elastic modulus rises from 20 GPa to 100 GPa, sleeper lateral resistance increases by 59 %, primarily due to enhanced particle interlocking and improved compressive resistance of the ballast bed. Microscopically, higher elastic modulus intensifies particle translational and rotational motion, elevates peak contact forces, and engages more particles in shear flow. Macroscopically, total deformation decreases under train loads, with elastic deformation proportion increasing while plastic deformation decreases. Suppressed particle translation but intensified rotation reflects that enhanced contact stiffness inhibits flow deformation. Elastic modulus variation alters load transmission pathways by modifying contact stiffness and reconfiguring force chain networks. This study provides theoretical support for the mechanical design of ballasted tracks.