Performance of Tire Cell–Reinforced Tracks under Multistage Cyclic Loading: Full-Scale Testing and Numerical Modeling

This paper presents a novel and comprehensive approach to minimizing track deformation by assembling recycled truck tire cells infilled with granular material in a square pattern as an alternative to a traditional capping layer (i.e., uppermost layer of subballast) constructed with compacted sandy gravel. A full-scale test track was constructed at the National Facility for Heavy-Haul Rail Testing, supported by numerical modeling using the finite element method, to evaluate the effectiveness of a tire cell assembly used as the capping layer beneath the ballast. This system builds on prior research demonstrating that a tire cell assembly, when infilled and compacted with granular material, forms a more confined and resilient substructure layer with enhanced energy dissipation capacity (i.e., higher damping ratio) that effectively limits lateral movement and reduces ballast breakage. In this study, multistage cyclic loading is applied to simulate heavy-haul freight trains with typical axle loads ranging from 20 to 35 t, subjected to equivalent loading–unloading frequencies of 10 and 15 Hz, corresponding to typical train speeds of 50 – 80 km / h . Test results on track settlements, lateral displacements, resilient modulus, ballast breakage are reported, with the infilled tire cells contributing to enhanced substructure stability. The presence of a semirigid capping layer beneath the ballast layer contributes to reduced lateral displacement of the track, while providing a robust and stiff foundation for the primary load-bearing ballast-sleeper system. The analysis of stress distribution with depth confirms that the tire cell–reinforced layer has contributed to an increase in the stiffness of the load-bearing stratum as well as an accompanying reduction of the stress transferred to the underlying softer subgrade. Even in the final loading stage under an increased simulated load of 35 t at 15 Hz, the track did not encounter any significant settlement. A finite element model was also developed and validated by full-scale experimental results, where the emphasis was placed more on the understanding of how tire cells would integrate within the track substructure to control stress distribution and deformation (mobilized strain).