https://doi.org/10.1051/epjconf/201714002028
A DEM study of oedometric compression of model granular materials Initial state influence, stress ratio, elasticity, irreversibility.
Université Paris-Est, Laboratoire Navier, UMR 8205, École des Ponts ParisTech, IFSTTAR, CNRS, France
* e-mail: mohamed-hassan.khalili@enpc.fr
** e-mail: jean-noel.roux@ifsttar.fr
*** e-mail: sebastien.brisard@ifsttar.fr
**** e-mail: jean-michel.pereira@enpc.fr
† e-mail: michel.bornert@enpc.fr
Published online: 30 June 2017
A DEM simulation study of spherical beads with elastic-frictional contacts in oedometric compression is carried out for a wide variety of initial states, differing in solid fraction Φ, coordination number z (independent of Φ in dense systems) and inherent anisotropy. Stress ratio K0 = σ2/σ1, along with z, Φ and force and fabric anisotropies are monitored in compressions in which axial stress σ1 varies by more than 3 orders of magnitude. K0 tends to remain constant if the material was already one-dimensionally compressed in the assembling stage. Otherwise, it decreases steadily over the investigated stress range. K0 relates to force and fabric anisotropy parameters by a simple formula. Elastic moduli may express the response to very small stress increments about the transversely isotropic equilibrated states, although oedometric compression proves an essentially anelastic process, mainly due to friction mobilization. Despite apparent nearly reversible increases of axial strain ϵ1 (or density Φ), especially in dense samples, internal state evolutions are strongly irreversible, as evidenced by changes in z and K0. Fabric changes are reflected by anisotropic elastic moduli.
© The Authors, published by EDP Sciences, 2017
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
