Macroscopic and Micromechanical Approaches to the Modelling of the Osmotic Swelling in Clays

The osmotic swelling in clays has been extensively studied at the physico-chemical scale. The present paper addresses the question of the modelling of this phenomenon from the mechanical point of view. First, the classical macroscopic thermodynamic framework for saturated porous continua is extended...

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Bibliographic Details
Published in:Transport in porous media 2003-01, Vol.50 (1-2), p.75-91
Main Authors: Dormieux, Luc, Lemarchand, Eric, Coussy, Olivier
Format: Article
Language:English
Subjects:
Activity coefficients
Chemical Sciences
Clay
Elasticity
Internal forces
Material chemistry
Modelling
Organic chemistry
Swelling pressure
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Summary:The osmotic swelling in clays has been extensively studied at the physico-chemical scale. The present paper addresses the question of the modelling of this phenomenon from the mechanical point of view. First, the classical macroscopic thermodynamic framework for saturated porous continua is extended in order to take into account the solid-salt interaction through the concept of macroscopic activity coefficient of the salt. The micromechanical approach then incorporates this interaction through the concept of swelling pressure which is used for describing the internal forces in the fluid phase at the microscopic scale. The results of a physico-chemical theory for the solid-salt interaction, such as the e.d.l. theory, can be introduced in both approaches. Each of them leads to the identification of a deviation, of chemical origin, to Terzaghi's effective stress principle. Besides, the micromechanical approach allows us to clearly differentiate the mechanical and the chemical parts of clay materials elasticity.
ISSN:0169-3913
1573-1634
DOI:10.1023/A:1020679928927