Evaluation of macroscopic soil model parameters using the discrete element method

The engineering properties of the granular materials are controlled by the physical characteristics of the particles, the fabric, the granular matrix and the state of the material. For these discontinuous materials, numerical modeling using continuum-based methods are not able to capture the complex microscale interactions that control the macro scale behavior into detail. On the other hand, with appropriate contact algorithms, provision for complex grain shapes/gradations and modeling of mechanical behavior using real size discrete particles, the Discrete Element Method has been used by researchers to simulate the behavior of granular materials at the microscale. The objective of this study is to highlight the applicability of the DEM over a range of laboratory tests, including the determination of maximum and minimum void ratio, geometric compression tests, and drained triaxial compression tests. The comparison of experimental and numerical results demonstrates the ability of the DEM to realistically model macroscopic soil behavior based on only a few parameters in the micro scale. We conclude that back-calculation of the parameters in the microscale based on few conventional laboratory tests along with the application of the DEM to simulate complex stress- and strain-paths, that cannot be easily realized in experiments, can be a procedure for the development, validation and calibration of the advanced constitutive models required for solving real geotechnical boundary problems numerically.