DEM analysis of soil fabric effects on behaviour of sand

The effects of initial soil fabric on the shear behaviour of granular materials are investigated by employing distinct element method (DEM) numerical analysis. Soil specimens are represented by an assembly of non-uniform sized spherical particles. DEM specimens that have different initial contact normal distributions were prepared at two different densities (loose and dense) and then isotropically consolidated triaxial tests were simulated with the following conditions: (a) different drainage conditions (undrained/drained), (b) different modes of shearing (compression/extension), and (c) different directions of shearing (vertical/horizontal). The numerical analysis results are compared qualitatively with the observed experimental data and the effects of initial soil fabric on resulting soil behaviours are discussed. The discussions include the effects of specimen reconstitution methods, effects of large preshearing, and anisotropic characteristics in drained and undrained conditions. The effects of initial soil fabric on the quasi-steady state are also investigated. The numerical analysis results can systematically explain that the observed experimental behaviours of sand are due principally to the effects of initial soil fabric. The outcome provides insights into the observed phenomena in microscopic view.