Investigation of the effective elastic parameters in the discrete element model of granular material by the triaxial compression test

• We investigated macroscopic effective elastic parameters in DEM of granular material.
• We proved that behaviour of material can be reproduced with DEM spherical particles.
• We calculated relationship between elastic moduli and the contact parameters.
• Numerical results are close to theoretical predictions for higher coordination number.

The general objective of the present paper is to improve the understanding of micromechanical mechanisms in granular materials and their representation in numerical models. Results of numerical investigations on micro–macro relationships in the discrete element model of granular material are presented. The macroscopic response is analysed in a series of simulations of the triaxial compression test. The numerical studies are focused on the influence of microscopic parameters on the initial response. The effect of the contact stiffness and friction coefficient on the effective elastic moduli is investigated. Numerical results are compared with the analytical estimations based on the kinematic Voigt's hypothesis as well as with selected numerical results of other authors. The comparisons show that a better agreement between the numerical and analytical results is observed for particle assemblies with higher coordination numbers. Higher coordination numbers are related to more compact specimens and for a given specimen can be associated with low values of the contact stiffness and a higher confining pressure.