Creep of saturated materials as a chemically enhanced rate-dependent damage process

TitleCreep of saturated materials as a chemically enhanced rate-dependent damage process
Publication TypeJournal Article
Year of Publication2007
AuthorsLB Hu, and T Hueckel
JournalInternational Journal for Numerical and Analytical Methods in Geomechanics
Volume31
Issue14
Start Page1537
Pagination1537 - 1565
Date Published12/2007
Abstract

Material behaviour that exhibits characteristics of creep induced by a spontaneous mineral dissolution enhanced by material damage is studied. It is believed that the characteristic rates of the chemical processes involved determine the time-rate dependence of the resulting strain. A basic model of a combined chemo-plastic softening and chemically enhanced deviatoric strain hardening for saturated geomaterials is presented. Chemical softening is postulated to occur as a consequence of the net mass removal resulting from dissolution and precipitation of specific minerals occurring at the damage-generated inter-phase interfaces. Closed and open systems are discussed. In the former case, deformation at constant stress results entirely from a local compensation mechanism between the chemical softening and strain hardening. The classical three stages of creep are interpreted in terms of mechanisms of dissolution and precipitation, as well as the variation in the reaction surface areas involved in the mass exchange. In an open system, the above local mechanism is enhanced by the removal of mass via diffusion of species affecting the mass balance. Such a system is addressed via a boundary value problem as shown in an example. Copyright © 2007 John Wiley & Sons, Ltd.

DOI10.1002/nag.600
Short TitleInternational Journal for Numerical and Analytical Methods in Geomechanics