Two-dimensional numerical investigation on bonding effect between particles of structured sands

After capturing the contact behaviours of idealized bonded granules in the contact model of discrete element method (DEM), the numerical investigation is carried out on bonding effect between particles of structured sands. First, the bonded granules are idealized by two aluminum rods glued together in a pre-defined model. The contact behaviours between the bonded rods are obtained by applying a set of mechanical tests. Secondly, a simple bond contact model is deduced from the measured results of the bonded rods and introduced in our two-dimensional DEM code (NS2D) to simulate a series of isotropic compression tests on the materials with different densities and bonding strengths. Finally, the DEM results are examined in comparison with the experimental data on artificially bonded sands obtained. The study shows that the DEM model is able to capture the main features of structured sands, such as variations of yielding and bulk modulus against the initial density or bonding strength. In addition, it is shown that the primary yielding is largely related to the bond breakage.