Discrete element modeling of the effect of real-shape ballast angularity on sleeper lateral resistance

The mechanical behavior of railroad trackbeds, especially their lateral resistance under dynamic train loads, is significantly influenced by ballast angularity. Using simulations using the Discrete Element Method and realistic particle geometries acquired through 3D scanning, this study examines the function of ballast particle angularity. An Artec Space Spider was used to scan and import five ballast samples into PFC3D, each of which had a unique size distribution and angularity index. To simulate a Single Tie Push Test, a B70 concrete sleeper, which is frequently found in European tracks, was modelled and put through lateral loading. Results for the standard No. 24 ballast gradation were compared with experimental data to validate the simulation framework, and the results indicated a high degree of agreement in the lateral force-displacement behavior. By examining changes in the particle size distribution, ballast degradation was measured, and the resulting Ballast Breakage Index and Breakage Ratio were calculated. Using accepted techniques, lateral resistance was calculated as the area under the displacement curve at 3.5 mm. According to the results, samples with more angular particles had lower degradation and higher lateral resistance. The importance of angularity in stabilising ballast layers under lateral loads was validated by regression analysis. These results offer guidance for better ballast selection and maintenance practices in the field of railway engineering.