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Effective stress concept in unsaturated soils: Clarification and validation of a unified framework
Author(s) -
Nuth Mathieu,
Laloui Lyesse
Publication year - 2008
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/nag.645
Subject(s) - terzaghi's principle , plane stress , stress (linguistics) , stress space , effective stress , oedometer test , geotechnical engineering , isotropy , context (archaeology) , saturation (graph theory) , constitutive equation , stress reduction , soil water , stress path , mathematics , structural engineering , geology , engineering , cauchy stress tensor , soil science , pore water pressure , finite element method , mathematical analysis , physics , psychology , philosophy , psychotherapist , linguistics , paleontology , combinatorics , quantum mechanics
The effective stress principle, conventionally applied in saturated soils, is reviewed for constitutive modelling purposes. The assumptions for the applicability of Terzaghi's single effective stress are recalled and its advantages are inventoried. The possible stress frameworks applicable to unsaturated soil modelling are reassessed in a comparative manner, specifically the Bishop's single effective stress, the independent stress variables approach and the generalized stress framework. The latter considerations lead to the definition of a unified stress context, suitable for modelling soils under different saturation states. In order to qualify the implications brought by the proposed stress framework, several experimental data sets are re‐examined in the light of the generalized effective stress. The critical state lines (CSLs) at different saturation states tend to converge remarkably towards a unique saturated line in the deviatoric stress versus mean effective stress plane. Theeffective stress interpretation is also applied to isotropic paths and compared with conventional net stress conception. The accent is finally laid on a second key feature for constitutive frameworks based on a unified stress, namely the sufficiency of a unique mechanical yield surface besides the unique CSL. Copyright © 2007 John Wiley & Sons, Ltd.