Does modifying the particle size distribution of a granular material alter its shear strength?

Author(s): 
Emilien Azéma, Sandra Linero, Nicolas Estrada, Arcesio Lizcano
Date: 
Monday, July 3, 2017
First presented: 
Powders and Grains
Type: 
Published paper
Category: 
Geotechnical

By means of two dimensional contact dynamics simulations, we analyzed the effect of the particle size distribution (PSD) on the shear strength of granular materials composed of un-breakable discs. We modelled PSDs with a normalized beta function, which allows for building S-shaped gradation curves, such as those that typically occur in soils. We systematically controlled and varied the size span and the shape of the PSD, and found that the shear strength is independent of both characteristics. This implies that PSD modification procedures such as material scalping (i.e., removing the smallest and/or largest particles in the sample) should not affect significantly the shear strength of the material composed of unbreakable discs. In order to explore the origins of the invariance of the shear strength with PSD, we analyzed the connectivity, force transmission, and friction mobilization in terms of anisotropies, finding that the constant shear strength is due to a subtle compensation of anisotropies.

Feature Author

Dr. Arcesio Lizcano

Arcesio is a civil engineer with more than 30 years of experience in geotechnical engineering including research and teaching in soil mechanics. He has extensive experience in engineering design and construction, including construction oversight of foundations, excavations, road embankments, retaining structures, and stockpiles and waste dumps.

Arcesio specializes in understanding the behaviour of sand and clays and applying that understanding to practical problems. He has contributed to civil and mining projects in Asia, Europe, Africa, North and South America. He has published over seventy papers in journals and conferences.

Soil Mechanics Specialist
PhD, Geotechnical Engineering
SRK Vancouver
SRK North America