Creep of Geomaterials due to the Coupled Damage and Spontaneous Mineral Dissolution

Abstract

A basic model of chemical softening, and chemically enhanced deviatoric strain - hardening for saturated geomaterials is presented. The aim is to simulate the material behavior that exhibits characteristics of creep induced by environmental conditions. Chemical softening is postulated to occur as a consequence of mineral dissolution and precipitation enhanced by the material damage. Dissolution of minerals in pore water is assumed to take place at the internal free surfaces not only of the initial pore space but also that generated during damage. The rate dependence of the processes of dissolution and precipitation renders also the resulting chemical softening behavior to be rate dependent. In this paper a closed system is discussed only, in which deformation at constant stress results entirely a from a local compensation mechanism between the chemical softening and strain hardening. Three stages of creep are interpreted in terms of mechanisms of dissolution and precipitation, as well as the variation in the reaction area involved in the mass exchange. An open system, these local mechanisms are enhanced by diffusion of species affecting the mass balance and need to be addressed via a boundary value problem, as described elsewhere.KeywordsPore WaterStrain HardeningClosed SystemMass ExchangeMaterial BehaviorThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.