A multiscale modeling of damage and time‐dependent behavior of cohesive rocks

Abstract

SUMMARYThe present paper deals with a micromechanical approach to modeling the time-dependent mechanical behavior of a class of cohesive geomaterials. The considered material is Callovo-Oxfordian argillite, which is mainly composed of three constituents: an elastoviscoplastic clay matrix, elastic quartz minerals, and elastic damaged calcite grains. The macroscopic constitutive law is obtained by adapting the incremental method proposed by Hill (J. Mech. Phys. Solids 1965; 13:89-101). Its unified formulation allows a description of not only the time-dependent behavior of the argillite but also its elastoplastic damage response. The developed model is first validated by comparison with finite element solutions and then it is applied to the prediction of argillites' macroscopic responses in connection with their mineralogical compositions. The validity of the model is checked through comparisons between the model's predictions and experimental data.

Modeling of Creep Behavior of an Argillaceous Rock by Numerical Homogenization Method

“…They have two different shapes and produce fewer deformations than other models. The simulation results established by the models of Abou-Chakra Guéry et al [26], and Bikong et al [28] agree on the result of the proposed model and together form the upper limit of the spindle. The sensitivity change of the inclusion volume was also analyzed by triaxial test simulations Fig.…”

“…The approach adopted in this investigation is similar to [30], in which the authors attempted to consider the Argillite as a composite material (inclusion-matrix) using a finite element numerical approach. The essential difference between this investigation and previous works [26] [27] [29] [23] is that the local behavior of the clay matrix is described by a primary creep model for modeling the creep behavior as simply as possible. The modeling methodology, the micromechanical model and the parameter identification method were validated by using a wide range of experimental result published in the literature.…”

“…Abou-Chakra Guéry et al [25] proposed a modified incremental homogenization method in which the elasto-viscoplastic behavior of the argillaceous rock was of the Perzyna type with a Drucker Prager plasticity criterion. This model was then extended by the same authors [26] in order to predict the macroscopic behavior in relation to the mineralogical composition. Recently, other contributions have enriched the micromechanical modeling of time dependent behavior, such as: Huang et al [27] with a new micromechanical model that takes into account porosity and mineral grains at two different scales.…”

A two-scale model for subcritical damage propagation

“…From such micro-scale considerations, Abou-Chakra Guery et al (2009) developed a model for argillite assuming it as a three-phase composite subject to viscous and damage effects. Also Nadot et al (2006) (see also Dartois et al (2009)) developed a viscoelastic damage model via a scale transition approach in which damage occurs by grain/matrix debonding.…”

Homogenization of anisotropic elastoplastic behaviors of a porous polycrystal with interface effects

“…Two important future developments of the present study are the following: Recalling that the main objective of the present micromechanical study is to understand the elastoplastic behavior of the studied clay matrix, the next step is to extend the proposed model by incorporating the effects of rigid quartz and calcite inclusions, which are present in Callovo‐Oxfordian argillite. This will be done in the framework of a meso‐macro upscaling procedure as already proposed by Abou‐Chakra et al (see also ) in the phenomenological context of a Drucker–Prager model for the clay matrix. After implementing a careful calibration method, it will be then possible to provide experimental verification and rigorous validation of the final model by comparing its predictions with the available data on the macroscopic response of the argillite. The saturation of Callovo‐Oxfordian argillite by water as well as a partially saturation has not yet been considered in the present study.…”