Fabric effect on the angle of repose in granular materials

In the present study, we perform a series of physical model experiments and numerical simulations to examine the effect of fabric orientation on angle of repose. The results show that with the deposition plane orientation angle θ varying from 0° to 90°, the angle of repose α reduces firstly and then rebounds, and the minimum values emerge at θ = 30° ~ 45°. Numerical analyses indicate that the microstructure reorganization becomes more intense as θ varies from 0° to 90°, making the anisotropy magnitude decrease and the principal anisotropy direction transit to a specific direction. With the analysis based on a conceptual model, we make a clarification on the fundamentals underlying the effect of fabric orientation on the angle of repose α. By introducing a θ-dependent coefficient, we propose an expression of α as a function of principal anisotropy directions (ϕn and ϕp) of the contact and particle orientations.