Numerical and Experimental Investigations of the Effect of Gradation and Shape of Particles on the Mechanical Behavior of Granular soils

Because testing on different materials often requires a lot of time and money, numerical simulation can be an acceptable method to avoid conducting several tests. One of the most effective methods to investigate the behavior of granular materials is discrete element method. This method, as a new approach, can simulate the behavior of material realistically, without implementing complex constitutive models (Wang et al, 2007; Shamsi and Mirghasemi, 2012; Tian et al, 2018). We know that the behavior of the particle assembly is influenced by the experimental test conditions, particle size distribution, particle shapes, etc. Previous researches show that particle shape has a significant effect on the mechanical behavior of granular soil (Tian et al, 2018). Therefore, to properly model the behavior of granules, it is better to simulate the particle shape as close to reality as possible. The main objective of this paper is to evaluate the effect of gradation and realistic particle shape on the mechanical behavior of granular soil in three dimensional discrete element method modeling in order to increase accuracy and precision of the simulation results. In this regard, in this study, irregular particles are modeled using a set of spheres that have different radii, overlap with each other and form a rigid object (clump) as shown in Fig. 1. Then, a series of consolidated drained triaxial compression tests have been performed on the specimens containing particles with various shapes. Finally, the results of the modeling were compared qualitatively with the experimental results.