Deformability of clays under non isothermal conditions



This paper presents the findings of an experimental study aimed at investigating some aspects of the thermo-mechanical behaviour of clays. ln particular, attention is focused on the influence of the stress history on the behaviour of soil when subjected to temperature variations and, conversely, on the influence of the thermal history on mechanical behaviour. Natural and emoulded clayey soils were subjected to temperature cycles in drained conditions. The results show that the variations of temperature produce irreversible volume change that is strictly dependent on the rate of viscous deformations exhibited by the solid skeleton when the thermal lead is applied. lt is shown that a temperature cycle on a normally consolidated clay produces an effect ‘quasi-preconsolidation' with a stiffness increment that depends on the subsequent stress path. The memory of the thermal cycle fades progressively moving away from the strain and stress state connected with the cycle. Finally, the analysis of the interaction between thermal and mechanical behaviours suggests some hypotheses on the nature of the irreversible deformations produced by temperature variations and about the similarities with viscous deformations of the solid skeleton.

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AUTORI: Burghignoli A., Desideri A., Miliziano S.
Numero di pagine: 227

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