A constitutive study of thermo-elasto-plasticity of deep carbonatic clays

Abstract

Argillaceous masses considered for potential nuclear waste repositories may exhibit significant space variability in their carbonate content. This may affect mechanical clay properties, such as strength or maximum apparent preconsolidation stress known to strongly depend on carbonate content. This paper investigates experimentally the dependence of thermo-hydro-mechanical behaviour of clays on carbonate content. The properties investigated are thermal strains, thermally induced over-consolidation, strength changes, destructuration, and thermally developed water pressure in undrained conditions. The experimental data are analysed in terms of a thermo-elasto-plasticity theory for clays, being an extension of Cam-clay model, modified to include the variability of the carbonatic content.

Response of soil subjected to thermal cyclic loading: Experimental and constitutive study

“…Only a few experimental results are currently available in such conditions (Campanella and Mitchell, 1968;Hueckel et al, 1998), and the physical mechanisms that control this behaviour have not yet been fully identified. In this framework, the goals of this paper are to experimentally investigate the volumetric response of a silty soil subjected to drained thermal cycles between 5 and 60°C and to propose a constitutive model that is able to reproduce the observed behaviour.…”

A double hardening thermo-mechanical constitutive model for overconsolidated clays

“…For example Hueckel et al [7,8] extended the elasto-plastic modified Cam-clay model to include the thermal effects following Prager's thermoplasticity theory. This model was modified later to include the variability of the carbonate content [9]; Lingnau et al [12] proposed two models to simulate the behavior of sand-bentonite mixtures at elevated temperatures: the isothermal pseudo-elastic model and the isothermal elastoplastic model; Modaressi et al [13] developed a cyclic thermo-visco-plastic model to take thermo-mechanical factors into account. Cui et al [5] proposed an elastoplastic model for saturated soils subjected to temperature changes within the framework of the Cam-clay model, but with particular attention to the volume-change behavior and the effects of the overconsolidation ratio; Graham et al [6] proposed a model which could predict how the heating and cooling affect the volume changes, the porewater pressures, and the strengths of both normally consolidated and overconsolidated soils; Laloui et al [10,11] proposed a cyclic thermo-elasto-plastic constitutive model to simulate the behavior of fine soils subjected to thermomechanical loading.…”

Thermo-mechanical constitutive modeling of unsaturated clays based on the critical state concepts

“…Furthermore, in these formulations, effect of temperature on state surfaces is not well defined, despite its importance on response of soil (e.g. Hueckel and Baldi, 1990;Lingnau et al, 1995;Hueckel et al, 1998;Cui et al, 2000;Graham et al, 2001).…”