. s:, J. Irazábal, F. Salazar, E. Oñate, J. Irazábal González
Conventional and high-speed train lines are being constructed all over the world with the objective of improving the mobility of both people and goods. Most of these infrastructures are built with railway ballast, a granular material whose main functions are resisting train loads and facing climate actions. The growth in popularity of railway infrastructures has led to an increasing interest in the development of numerical models to evaluate their performance and improve their maintenance. To this respect, the Discrete Element Method (DEM) is an approach that considers the discontinuous nature of granular materials, such as railway ballast. Moreover, it can also be used to compute the behaviour of continuum materials, such as rails and bearing plates, applying the so-called bonded DEM. The code used is developed within DEMPack, a specific software tool for modelling physical problems using the DEM. After evaluating the different geometrical alternatives for representing railway ballast and considering the high amount of material involved in the full-scale tests (more than 130,000 particles) the calculations were carried out using the most efficient option, spheres with rolling friction. This geometrical simplification is not suitable for small-scale tests, however, previous analysis showed that it is accurate enough for reproducing the macroscopic behaviour of the ballast layer. The numerical results correctly capture the effect of changing several parameters such as ballast compaction, inter-particle friction or grain size. It can be concluded that the DEM increases the possibilities for analysing innovative solutions aiming to improve ballasted tracks design, maintenance and performance, since real case-scenarios can be studied with enough accuracy and feasible time.
Published on 01/01/2019
Licence: CC BY-NC-SA license
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