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Thermomechanical model of hydration swelling in smectitic clays: II three‐scale inter‐phase mass transfer: homogenization and computational validation
Author(s) -
Murad Márcio A.
Publication year - 1999
Publication title -
international journal for numerical and analytical methods in geomechanics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.419
H-Index - 91
eISSN - 1096-9853
pISSN - 0363-9061
DOI - 10.1002/(sici)1096-9853(199906)23:7<697::aid-nag990>3.0.co;2-#
Subject(s) - homogenization (climate) , swelling , materials science , geotechnical engineering , mass transfer , geology , composite material , chemistry , chromatography , biodiversity , ecology , biology
In Part I a two‐scale thermomechanical theory of expansive compacted clays composed of adsorbed water and clay platelets was derived using a mixture‐theoretic approach and the Coleman and Noll method of exploitation of the entropy inequality. This approach led to a two‐scale model which describes the interaction between thermal and hydration effects between the adsorbed water and clay minerals. The purpose of this paper is twofold. Firstly, partial results toward a three‐scale model are derived by homogenizing the two‐scale model for the clay particles (clusters of clay platelets and adsorbed water) with the bulk water (water next to the swelling particles). The three‐scale model is of dual porosity type wherein the clay particles act as sources/sinks of water to the macroscale bulk phase flow. One of the notable consequences of the homogenization procedure is the natural derivation of a generalized inter‐phase mass transfer equation between adsorbed and bulk water. Further, variational principles and finite element approximations based on the Galerkin method are proposed to discretize the two‐scale model. Numerical simulations of a bentonitic clay used for engineered barrier of nuclear waste repository are performed and numerical results are presented showing the influence of physico‐chemical effects on the performance of the clay buffer. Copyright © 1999 John Wiley & Sons, Ltd.