The relationship between contact-based and void-based fabrics of granular media

Fabrics of granular media play an important role in understanding sophisticated soil behaviors and developing constitutive models. In this study, the evolution of fabric anisotropy in terms of both contact normals and local void distributions under drained and undrained loading conditions is explored using DEM simulations. It is observed that the anisotropy degree of both contact-based and void-based fabric increases when granular packing is subjected to monotonic loading. However, the mobilization of the contact-based fabric is much faster than that of the void-based fabric. The contact-based fabric is significantly influenced by static liquefaction, while the influence of static liquefaction on the void-based fabric is almost negligible. Furthermore, one of the descriptors by which to quantify the void-based fabric, Ed, has a strong correlation with the void ratio and mean effective stress. Various manifestations of dilative (or contractive) behaviors of granular soils can be further unified by the evolution of Ed.