Discrete element modelling of two-layered ballast in a box test

Li, Huiqi; Mcdowell, Glenn

Abstract

It has been recently reported that ballast comprising differently graded layers helps to reduce track settlement. The main goal of this paper is to provide micro mechanical insight about how the differently layered ballasts reduce the settlement by employing DEM and thus propose an optimum design for two-layered ballast. The DEM simulations provide sufficient evidence that the two-layered ballast works by preventing particles from moving laterally through interlocking of the particles at the interface of the different layers in a similar way to geogrid. By plotting the lateral force acting on the side boundary as a function of the distance to the base, it is found that the walls in the region of 60-180 mm above the base alway support the largest lateral forces and therefore this region might be the best location for an interface layer. However, considering the weak improvement in performance by increasing the thickness of the layer of scaled (small) ballast from 100 mm to 200 mm, it is suggested that it is best to use the sample comprising 100 mm scaled ballast on top of 200 mm standard ballast as the most cost effective solution.

Citation

Li, H., & Mcdowell, G. (2020). Discrete element modelling of two-layered ballast in a box test. Granular Matter, 22, Article 76. https://doi.org/10.1007/s10035-020-01046-6

• Journal Article Type: Article
• Acceptance Date: Jul 28, 2020
• Online Publication Date: Aug 28, 2020
• Publication Date: Aug 28, 2020
• Deposit Date: Aug 5, 2020
• Publicly Available Date: Aug 29, 2021
• Journal: Granular Matter
• Print ISSN: 1434-5021
• Publisher: Springer Verlag
• Peer Reviewed: Peer Reviewed
• Volume: 22
• Article Number: 76
• DOI: https://doi.org/10.1007/s10035-020-01046-6
• Public URL: https://nottingham-repository.worktribe.com/output/4812402
• Publisher URL: https://link.springer.com/article/10.1007/s10035-020-01046-6