Shape or friction? Which of these characteristics drives the shear strength in granular systems?

¹ Department of Mechanical Engineering, Chiang Mai University, Chiang Mai, Thailand
² LMGC, Université de Montpellier, CNRS, Montpellier, France
³ Institut Universitaire de France (IUF), Paris, France
⁴ Departamento de Ingeniería Civil y Ambiental, Universidad de Los Andes, Bogotá, Colombia

^* e-mail: itthichai.p@cmu.ac.th

Published online: 7 June 2021

Abstract

The shape of the particles and local friction, separately, are known to strongly affect the macroscopic properties of an assembly of grains. But the combined effects of these two parameters still remain poorly described. By means of extensive two dimensional contact dynamics simulations, we perform a systematic analysis of the interplay between friction and shape on strength properties of granular systems. The shape of the particles is varied from disks to triangles, while the friction is varied from 0 to 0.7. We find that the macroscopic friction first increases with angularity, but it may decline (for low friction values), saturate (for intermediates friction values), or continue to increase (for large friction values) for the most angular shapes. In other words, the effect of the particle’s angularity on the shear strength depends on the level of sliding friction. In contrast, the effect of local friction on the shear strength does not depend on the specific properties of shape. The results presented here highlight the subtle coupling existing between shape and friction effects.