On the incremental behaviour of sands at high stresses

The mechanical behaviour of granular materials is characterized by strong non-linearity and irreversibility. In particular, particle breakage will induce additional plastic deformations beyond those which might be expected for a rigid particle assumption. When defining a constitutive model, experimental data on the nature of the incremental response of the material is desirable. However, the experiments are very challenging and therefore test simulations using the discrete element method (DEM) are very useful. In this work, the incremental behaviour of crushable granular soils is investigated using the DEM by simulating 3D axisymmetric stress probes experiments on a Fontainebleau sand analogue. Particle breakage is permitted and the initial high stress condition is such that crushing will occur along some of the loading directions. The results show that particle crushing induces a change in the direction of the plastic flow and that this direction is independent of the loading path.