Implementation of real contact behaviour in the DEM modelling of triaxial tests on railway ballast

In the Discrete Element modelling of soils, micromechanical behaviour at contacts has often been considered to have a minor influence on macromechanical response, leaving basic theoretical models (e.g., Hertz) describe contact response in normal direction. A realistic description may be crucial especially when investigating small strain ranges. Recent experimental inter-particle loading tests gravel suggest that classic fail reproduce certain mechanical features, roughness is significant. Here, some these observations, including softer than Hertz model under direction, and plasticity unloading, are implemented DEM for simulation railway ballast. The features stiffness highlighted. analysis carried out show how each contact-level introduced affects macroscopic response.