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Critical State Soil Mechanics Revisited: Fabric Effects

Objective

The theory of Critical State Soil Mechanics (CSSM) has become a paradigm within the framework of which elastoplastic soil constitutive models have been developed for the last 50 years. The present project will constructively challenge this paradigm from a missing fundamental perspective, namely the effect of soil fabric on the premises of CSSM.

The current CSSM postulates that at critical state the stress and void ratios reach critical values with no reference to orientational aspects of the soil fabric, such as particles long axes, contact normals or void vectors statistical orientations. Thus, several soil mechanical response characteristics associated with fabric anisotropy cannot be adequately or even correctly described within the existing theory. The hypothesis that an evolving soil fabric tensor must also acquire a critical value for critical state to occur will be investigated by theoretical, numerical and experimental means, including continuum and discrete elements methods (DEM) of analysis for cohesive and cohesionless soils, X-ray Computed Tomography studies on real soil samples, and triaxial, biaxial and hollow cylinder experiments. The results of this investigation will be used to propose a new enhanced CSSM theory with fabric playing a distinct role. Particular tasks will include the derivation of an objective rate equation of evolution of the fabric tensor, the formulation of classes of constitutive models for sands and clays within the new fabric-enhanced framework of CSSM, and the Finite Elements analysis of selected geomechanics boundary value problems illustrating the effect of soil fabric by comparing the results with and without fabric effects.

Successful completion of this project will change the way Soil Mechanics is taught at Universities and applied in advanced analysis of geomechanics problems, a field of increasing social impact in regards to hazard mitigations related to earthquakes and landslides.

Call for proposal

ERC-2011-ADG_20110209
See other projects for this call

Funding Scheme

ERC-AG - ERC Advanced Grant

Host institution

NATIONAL TECHNICAL UNIVERSITY OF ATHENS - NTUA
Address
Heroon Polytechniou 9 Zographou Campus
15780 Athina
Greece
Activity type
Higher or Secondary Education Establishments
EU contribution
€ 1 703 000
Principal investigator
Ioannis Dafalias (Prof.)
Administrative Contact
Georgia Mertzelou (Ms.)

Beneficiaries (4)

UNIVERSITE JOSEPH FOURIER GRENOBLE 1

Participation ended

France
Address
Avenue Centrale, Domaine Universitaire 621
38041 Grenoble
Activity type
Higher or Secondary Education Establishments
Administrative Contact
Yann Le Roux
NATIONAL TECHNICAL UNIVERSITY OF ATHENS - NTUA
Greece
EU contribution
€ 1 703 000
Address
Heroon Polytechniou 9 Zographou Campus
15780 Athina
Activity type
Higher or Secondary Education Establishments
Principal investigator
Ioannis Dafalias (Prof.)
Administrative Contact
Georgia Mertzelou (Ms.)
UGA-Université Grenoble Alpes
France
EU contribution
€ 143 000
Address
621, Avenue Centrale
38401 Saint Martin D'heres
Activity type
Higher or Secondary Education Establishments
Administrative Contact
Aurelie Diringer-Dagorne (Ms.)
CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CNRS
France
EU contribution
€ 78 000
Address
Rue Michel Ange 3
75794 Paris
Activity type
Research Organisations
Administrative Contact
Guillaume Rochet (Dr.)