A micromechanics-based model for sand-silt mixtures

Zhen-Yu Yin (1, 2) , Jidong Zhao (3) , Pierre-Yves Hicher (2)

1 Shanghai Jiao Tong University [Shanghai]
2 GeM - Institut de Recherche en Génie Civil et Mécanique
3 HKUST - Hong Kong University of Science and Technology

Experimental observations have shown the significant impact of fines or coarse grains on the behavior of sand-silt mixtures. To describe the behavior of sand-silt mixtures under both drained and undrained conditions, this paper presents a mathematical model based on a micromechanical approach. The novelty of this model is the introduction of the equivalent mean size and the evolution of the position of the critical state line with fines content for various sand-silt mixtures. The predictive capability of the model was evaluated by comparing the model simulations with experimental results on undrained triaxial tests of Foundry sand-silt mixtures with fines content, f(c) = 0-100% and Ottawa sand-silt mixtures with fines content f(c) = 0-50%, and on drained triaxial tests of Hong Kong Completely Decomposed Granite (HK-CDG) mixtures before and after erosion. The predicted local behavior in the contact planes has also been examined. It shows that all local contact planes are mobilized to different degrees in terms of local stress and strain and that a few active contact planes contribute dominantly to the deformation of the assembly, leading to an anisotropic global behavior when the soil is subjected to external loading.

Mots clés: Micromechanics; Constitutive relations; Elasto-plasticity; Sand Silts; Critical state

Domaines: Mécanique [physics.med-ph]; Matériaux

Zhen-Yu Yin, Jidong Zhao, Pierre-Yves Hicher. A micromechanics-based model for sand-silt mixtures. International Journal of Solids and Structures, 2014, 51 (6), pp.1350-1363. ⟨10.1016/j.ijsolstr.2013.12.027⟩. ⟨hal-01004847⟩