A CONSTITUTIVE STUDY OF THERMO-ELASTOPLASTICITY OF DEEP CARBONATIC CLAYS

Argillaceous masses considered for potential nuclear waste repositorie s may exhibit significant space variability in their carbonate content . This may affect mechanical clay properties, such as strength or maxi mum apparent preconsolidation stress known to strongly depend on carbo nate 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-co nsolidation, strength changes, destructuration, and thermally develope d water pressure in undrained conditions. The experimental data are an alysed 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. (C) 1998 John Wiley & Sons, Ltd.