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Shear strength and microstructure of polydisperse packings: The effect of size span and shape of particle size distribution

Emilien Azema, Sandra Linero, Nicolas Estrada, Arcesio Lizcano
Monday, August 14, 2017
First presented: 
Physical Review E
Published paper

By means of extensive contact dynamics simulations, we analyzed the effect of particle size distribution (PSD) on the strength and microstructure of sheared granular materials composed of frictional disks. The PSDs are built by means of a normalized β function, which allows the systematic investigation of the effects of both, the size span (from almost monodisperse to highly polydisperse) and the shape of the PSD (from linear to pronouncedly curved). We show that the shear strength is independent of the size span, which substantiates previous results obtained for uniform distributions by packing fraction. Notably, the shear strength is also independent of the shape of the PSD, as shown previously for systems composed of frictionless disks. In contrast, the packing fraction increases with the size span, but decreases with more pronounced PSD curvature. At the microscale, we analyzed the connectivity and anisotropies of the contacts and forces networks. We show that the invariance of the shear strength with the PSD is due to a compensation mechanism which involves both geometrical sources of anisotropy. In particular, contact orientation anisotropy decreases with the size span and increases with PSD curvature, while the branch length anisotropy behaves inversely.

Full paper available at Physical Review E (Phys. Rev. E 96, 022902 – Published 14 August 2017).

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 United Kingdom