Formulation and Evaluation of the Ballast Shear Interlocking Coefficient based on Analytical, Experimental, and numerical Analyses

The interaction among ballast particles, known as ballast shear interlocking (BSI), significantly influences the dynamic responses of railway track. This research presents a meticulously derived mathematical formulation for calculating BSI stiffness, which is then validated through experimental data obtained from a novel laboratory test procedure. The accuracy of the BSI formulation is demonstrated by its successful prediction of BSI properties in laboratory tests. Additionally, a numerical layered model is introduced to evaluate the sensitivity of the proposed formula to the mechanical and dynamic attributes of the ballasted track. This model highlights the resilience of tracks and emphasizes the critical role of BSI effects in railway track design, offering insights into parameters affecting track behavior. The study comprehensively explores ballast behavior, emphasizing the importance of BSI in track resiliency and advocating for its precise consideration in railway track design, modeling, and maintenance to ensure operational safety and efficiency. The developed methodology not only enhances the modeling of ballasted railway tracks asmulti-layer systems but also advances the assessment of shear inter-locking effects through laboratory testing.