CALIBRATION OF RAILWAY BALLAST DEM MODEL

The ballast of the railway track is constantly changing due to dynamic forces of train traffic that results in the crushing of the rocks. The feasibility to simulate each particle makes the discrete element method (DEM) suitable for the task. Different DEM particle models are introduced in our paper and the adequate one was chosen. This new method is based on crushable convex polyhedral elements and random shape generation via Voronoi tessellation and is implemented in the Yade DEM simulation software. The particle geometry is validated via comparing the simplified shape of natural rough rocks and the randomly generated ones. A 3D scanner was used to digitize the natural rocks. The crushing behaviour is tested as well. The validation of interaction laws and the calibration of the micro parameters is necessary to create a DEM material model with a realistic behaviour. In the calibration process Hummel device is modelled, which provides well measurable parameters for comparing simulation and measurement results.