Role of Scaling Up Particle Size in Principal Stress Rotation under Simple Shear

The presence of principal stress rotation (PSR) in granular materials is a significant signature for engineering practices such as slopes, caverns, and silos. Multiscale modeling of granular behavior generally features scaled-up particles. Yet, the effect of scaling up particle size (SUPS) on the evolution of PSR in granular materials has rarely been revealed. This paper investigates the role of SUPS in the characteristics of PSR under various packing densities and vertical stress levels. Its role is further interpreted by fabric anisotropy from a micromechanical perspective. It is found that SUPS, packing density, and vertical stress level greatly affect the evolution of PSR and non-coaxiality. Packing density can further affect the relationship between the scaling factor and PSR. This is closely related to generalized fabric and fabric anisotropy in the direction of shear in granular material. The research outcomes are enlightening for the application of SUPS in future large-scale engineering practice.