Optimal design and application of geogrid for ballasted track stabilization in high-speed railways

This study investigates the optimal design parameters and installation location for geogrid stabilization in ballasted tracks under high-speed train loads. By integrating discrete element simulations with full-scale model tests, the performance of ballasted tracks was evaluated across various geogrid aperture sizes, stiffnesses, and installation locations. Multiple ballast gradations and trackbed compaction levels were also analyzed to ensure the generality of the results. The discrete element simulations indicate that a geogrid with an aperture size-tomedian ballast gravel size ratio of 0.83 and a stiffness of approximately 2.3 kN/m is most effective in minimizing trackbed settlement. Furthermore, installing the geogrid immediately above the subballast surface provides the greatest constraints on ballast displacement and rotation, while most effectively reducing trackbed settlement. Full-scale model tests involving millions of wheel-axle load cycles at moving speeds of up to 360 km/ h and axle loads of up to 25 t corroborate these findings, confirming the reliability and practical applicability of the optimal geogrid parameters and installation locations identified through discrete element simulations. This research offers evidence-based guidelines for optimal design of geogrid-stabilized ballasted tracks under practical railway service conditions, thereby extending maintenance intervals and improving long-term performance.