Investigation of Railway Ballast Breakage Through Large-Scale Triaxial Tests and a New Particle Breakage Approach in Discrete Element Modeling

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Crushed aggregates with irregular shapes and sharp corners are preferred ballast materials to ensure proper track bearing capacity because of good contact between the particles. Meanwhile, crushed aggregates are prone to deterioration and breakage under repeated train loads. The effect of particle degradation on the mechanical behavior of ballast has been investigated before, but previous research rarely separates ballast breakage during sample compaction from breakage during shearing. This study investigates ballast particle breakage at different stages through large-scale triaxial tests and discrete element modeling. The results show that corner breakage is the primary particle breakage mode and mostly happens during compaction instead of during the shearing process. The results also indicate ballast corner breakage during sample compaction would increase the peak strength of the ballast but would not change Young’s modulus. A rubber pad is strongly recommended to reduce ballast breakage during the triaxial test sample compaction.