The main objective of the project is the development of a numerical modeling tool, based on the discrete element method (DEM) for the analysis of the behavior of the  sand-fouled railway ballast.
The great development of high speed railways all around the world has arisen new technology challenges. Spanish companies and government agencies are involved in the design, construction and maintenance of some of the most important high-speed lines, such as the Haramain railway, which will connect the holy cities of Medina and Mecca, in Saudi Arabia.
Both in this and in similar lines, there is concern about the effect of sand contamination in the behavior of the ballast bedding. Several agents are currently working on the development of solutions to this potential problem on several fronts: a) to develop prevention measures for sand retention, b) to optimise maintenance by analysing the the effects of the amount of fouling on the ballast resistance.
These studies are being carried out via physical modeling (in our country, in the Geotechnical Laboratory of Railway Structures at CEDEX). Although these tests can be perfomed with the existing premises and technical capacity, they are very expensive and partially limited by the capacity of the experimental facilities.
Globally, only the groups of Indraratna, in Australia, and Tutumluer, in US, have published preliminary results dealing with the numerical modeling of fouled ballast. Although both consider other sources of ballast fouling, such as broken ballast stones, powder from the conveyed material in mining railways or infiltration from the subballast, these studies showed the interest of the community in the analysis of the problem and the limitations of the existing numerical tools: the lack of accuracy in the reproduction of the particles shape, the high computational cost, and the consideration of appropriate contact laws.
The project will contribute to a better understanding of the effect of ballast contanimation and allow testing potential solutions to improve its behavior in accidental situations. The result may also be applied in related fields, such as in the analysis of the performance of artificial ballast.
Likewise, the advances in numerical modeling can contribute to the application of such tools to optimise processes in which granular materials play a key role, such as in the food, mining or pharmaceutical industries, among others.
The proposal responds to the Challenge for Smart, Green and Integrated Transport, some of whose priorities are fully aligned with the objectives of the project as the "development of techniques, methodologies and tools for evaluation and risk reduction," or "research and application of new advanced materials for transportation" In addition, the practical orientation of the project and the sector in which it is framed can contribute to "strengthen the international leadership of the Spanish economy."

  Video 1: Shear box test.

Video 2: Velocity of ballast particles due to high speed train action.