Some tests allowed to analyse at macroscopic and microscopic levels, the thermo-hydro-mechanical behaviour of swelling and unswelling clayey rocks. The mechanical behaviour was studied by oedometric cyclic tests w th and without measurement of the radial stress, as well as undrained compression triaxial tests at different confining pressures. The influence of the consolidation pressure on the textures was analysed from results of porosimeter and BET tests. These tests allowed to point out an elasto-plastic behaviour during the loading for different swelling and unswelling clayey rocks. In the case of the swelling rocks, the unloading and the reloading curves showed hysteresis loops, which proved the existence of irreversible strains and an elasto-plastic behaviour. The k₀ coefficient for the different rocks could be valued by linear relation with the stresses ratio q/p'. Thus for the normally consolidated states, the variations of the external stress are level-headed by the evolution of the stress of contact : δσ_ext = δσ_c. In return for the overconsolidated states and in the case of the swelling clayey rocks, the variations of the external stress are compensaed by the physico-chemical repulsion stress: δσ_ext = δσ_R-I. To study the thermo-mechanical behaviour, we performed on one hand isothermal tests on some oedometric and undrained triaxial paths, and on the other hand thermal cycles under mechanical constant loading at normally and over consolidated states on some oedometric paths. The anisotropy of the strain under thermal solicitations and the irreversible strain of clayey rock textures were studied. Thus they allow to associate a tensorial operator, the thermal stress σ_T to thermo-mechanical solicita ions. The main phenomena due to the hydro-mechanical behaviour of highly compacted clayey rocks were pointed out by oedometric and trixial tests at constant suction and by sorpt on desorption cycles. So sorption desorption tests show two domains: a quasi saturated domain for which the strains are isotropic and a no saturated one characterised by reversible anisotropic strain. A tensor of capillary stress σ_cap is suggested in order to translate these strains. So in the general case of thermo-hydro-mechanical solicitations, the variations of external stress are equilibrated by the contact stress (OCR = 1) or repulsion stress (OCR > 1), and by the thermal stress and the capillary stress. σ_ext = σ_c + σ_cap + σ_T (OCR = 1) and σ_ext = σ_R + σ_cap + σ_T (OCR > 1).

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   |wiki=    Ticri/CIDE
   |area=    OcrV1
   |flux=    Main
   |étape=   Exploration
   |type=    RBID
   |clé=     Pascal:98-0090053
   |texte=   Expériences de laboratoire sur le comportement thermo-hydro-mécanique de matériaux argileux remaniés gonflants et non gonflants
}}