Meso-structure organization in two-dimensional granular materials along biaxial loading path
Zhu, H.X. ; Nicot, F. ; Darve, F.
Type de document
Article de revue scientifique à comité de lecture
Affiliation de l'auteur
IRSTEA GRENOBLE UR ETGR FRA ; IRSTEA GRENOBLE UR ETGR FRA ; GRENOBLE INP UMR 5521 L3SR FRA
Résumé / Abstract
In 2D granular material, column-like structures, called force-chains (FCs), are formed as force transmission tunnels that carry a major external loading. The movement of FCs is highly correlated to the strength and the volumetric behavior of the granular matter. Since FC stability is ensured by the confining structures surrounding them, these confining structures must be quantitatively characterized to investigate the moving pattern of FCs and significant mechanical behaviors of granular materials. In this paper, the meso-scale, a scale larger than the single contact scale (the micro-scale) and smaller than the macro-scale, is introduced such that in this scale the organization and structure among contacts can be characterized by the topology of the meso-structures (called loops). Then the interaction between the FC and its surrounding meso-structures is investigated. This study investigated two aspects: how the FC affects the geometry of the material fabric on the meso-scale, which is constituted of meso-structures; and, the way the meso-structures affect the FC's behavior. The results show that the material is highly heterogeneous on the meso-scale, depending on the distance to the FC. The FC's surrounding area is observed to have greater dilatability than other areas, because it is better able to generate loose structures on the meso-scale. Hence, the FC's adjacent areas can be seen as the main source of the global dilatancy. In contrast, FC movability, a concept closely related to FC instability, is observed to depend to a large extent on the nature of its surrounding meso-structures. As a result, depending on the initial meso-structures, stress boundary conditions will direct dilatancy or contractancy. Finally, the life cycle of the FCs is presented in relation with their confining meso-structures.
International Journal of Solids and Structures, vol. 96, p. 25 - 37