Modelling of deformation response and chemo-mechanical coupling in chalk

Abstract

A constitutive relation is derived for describing the mechanical response of chalk. The approach is based on a phenomenological framework which employs chemo-plasticity. The properties of the material are assumed to be affected by the physico-chemical processes that occur through the interaction between the skeleton and the pore fluid. The underlying mechanism is discussed by invoking a micromechanical analysis. The performance of the framework is illustrated by examining the evolution of mechanical characteristics in the presence of different pore fluids

Effects of mineral suspension and dissolution on strength and compressibility of soft carbonate rocks

“…iii) Intergranular pressure solution (Rutter, 1976): is a mechanism whereby the stress concentration at grain contacts causes local dissolution, transport of the solutes out of the contact and precipitation on the less stressed faces of the grains. Although it is often invoked (Renard et al, 2005;Le Guen et al, 2007) to explain the long-term deformation and failure of porous rocks in the presence of water, a very fast dissolution (≈8 h) of grain contacts may occur even in the short term, as noticed by Pietruszczak et al (2006) for chalk. iv) Subcritical cracking: even though it is very often considered that this weakening effect of water is more significant in the long term, it has sometimes been invoked to explain the short-term brittle behaviour of silicate rocks (e.g.…”

Mechanical and physical behavior of high-porosity chalks exposed to chemical perturbation

“…Chemical effects due to reactions between the chalk framework and the injected water are one of the major mechanisms in the so-called water weakening processes (Newman, 1983;Rhett and Teufel, 1991;Teufel and Rhett, 1992;Piau and Maury, 1994;Risnes and Flaageng, 1999;Risnes et al, 2005;Madland et al, 2011). Chemical dissolution precipitation have been investigated through various approaches such as numerical simulations (Pietruszczak et al, 2006;Lydzba et al, 2007;Hueckel and Hu, 2007), experimental studies (Hellmann et al, 2002b), as well as microscopic studies (Hellmann et al, 2002a). Despite numerous research, integrated study on direct correlation of dissolution precipitation effects and the mechanical properties are, however, limited.…”

A model for pore‐fluid‐sensitive rock behavior using a weathering state parameter

“…Models for rate-dependent behavior in their formulation, including overstress models [22,[48][49][50][51]; rate-type models [52][53][54]; and chemoplastic models based on mechanics of pressure solution [55], describe inelastic strain rate as a function of the proximity between the current stress point and a reference surface in stress space ( Figure 6(b)). …”