Stress-force-fabric relationship for planar granular materials

This paper presents the theoretical development of a relationship between the average stress components and the micromechanical fabric anisotropy characteristics within assemblies of planar particles. The main feature of the modified formulation is the ability to consider both inherent and induced anisotropy conditions within the assembly. This was achieved by amending the definition of the contact vector between particles in the stress-force-fabric relationship. By using numerical discrete-element method (DEM), a series of inherently anisotropic granular materials were simulated in order to verify the accuracy of the proposed formulation. In the simulations, the geometry of the particles was chosen to be irregular polygons. The shear capacity of the assemblies during the loading process was calculated from direct measurement of macroscopic stress components, and from anisotropy fabric parameters. By comparing the results, it is shown that reasonable agreement exists between the calculated and measured values.