Grading-Dependent Behavior of Granular Materials: From Discrete to Continuous Modeling: Fid-Bau Portal

Grading-Dependent Behavior of Granular Materials: From Discrete to Continuous Modeling

Li, Gang / Liu, Ying-Jing / Dano, Christophe / Hicher, Pierre-Yves

Abstract

The aim of this paper is to investigate the effect of soil grading on the stress-strain and the critical-state behavior of granular materials from idealized spheres to natural soils as well as from discrete to continuous modeling. The three-dimensional discrete-element method has been applied to study the mechanical behavior of idealized granular materials. The results confirm that the critical-state line (CSL) shifts downward as grading broadens with an increase of the coefficient of uniformity $C_{u}$ . An exponential relationship between the critical-state parameters and the coefficient of uniformity $C_{u}$ can then be established. Furthermore, experimental investigations on an artificial material (glass beads) and a natural material (Hostun sand) were carried out. The experimental results confirm the grading dependency of the critical-state behavior, and a similar relationship between CSL and $C_{u}$ , for both glass beads and natural sand, extending previous literature results for high $C_{u}$ values up to 20. Moreover, the experimental results show that the CSL tends to stabilize when the coefficient of uniformity $C_{u}$ becomes higher than 10. Based on all test results, a simple elastoplastic model accounting for the influence of the grain size distribution (GSD) on the mechanical behavior of granular materials has been developed within the framework of critical-state soil mechanics. Comparisons between experimental results and simulations show that the model can accurately reproduce the mechanical behavior of granular materials with different GSDs.