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Formulation of a three‐dimensional rate‐dependent constitutive model for chalk and porous rocks
Author(s) -
Hickman R. J.,
Gutierrez M. S.
Publication year - 2006
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.546
Subject(s) - viscoplasticity , geomechanics , constitutive equation , strain rate , geotechnical engineering , porous medium , porosity , geology , scaling , mechanics , stress (linguistics) , yield surface , materials science , thermodynamics , mathematics , geometry , finite element method , composite material , physics , linguistics , philosophy
Rate‐dependent behaviour of chalk and other porous rocks has undergone widespread study in geomechanics due to its implications on the performance of engineering structures. We present a rate‐dependent constitutive model for chalk and other porous rocks with several new features. The model formulation is based on a viscoplastic rate‐lines approach in which the axial strain rate depends on the proximity of the stress point to an elliptical reference surface. A non‐associated viscoplastic potential surface and an axial scaling algorithm are used to determine the viscoplastic strain components. The model predicts that axial yields stress varies as a power function of applied axial strain rate, as shown by published laboratory data. Comparisons with published experimental data indicate that the model is capable of reproducing observed rate‐dependent behaviour of chalk under a variety of loading conditions. Copyright © 2006 John Wiley & Sons, Ltd.