Abstract
When discrete element method (DEM) simulations are carefully coupled with equivalent physical experiments, conclusions about the micro-mechanics of underlying the observed material response can be made with confidence. A novel approach to simulating triaxial tests with DEM using circumferential periodic boundaries has been developed by the authors. In an earlier study, this approach was validated experimentally by considering a series of laboratory monotonic triaxial tests on specimens of uniform and non-uniform steel spheres. The current paper extends this previous research by simulating the response of specimens of about 15,000 steel spheres subject to unload/reload cycles in quasi-static triaxial tests. In general, good agreement was attained between the physical tests and the DEM simulations. The paper also discusses use of the DEM simulation results to explore the particle-scale mechanics during the load reversals.