In this study

a temperature-controlled triaxial apparatus was used to investigate the volume deformation behavior of saturated clay subjected to thermal cycles in drained conditions.It was found that the thermally induced plastic volumetric strain accumulated with the number of thermal cycles and then leveled off.When the specimens after thermal cycles were loaded to a normal consolidation state again

the subsequent temperature change can still lead to irreversible volume changes.The magnitude and the trend of the volumetric strains were similar to those under the initial thermal cycles.The thermally induced volumetric strain was mainly influenced by the overconsolidation ratio（OCR）and was irrelevant to the value of the stress level.At higher OCRs

the thermally induced volumetric strain was small

and the strain accumulation rate was high.On the basis of the generalized plasticity theory

a constitutive model was proposed to model the volume deformation behavior of saturated clays subjected to thermo-mechanical loads.The hardening effect of the thermally induced volumetric strain on the yield stress was accounted in the model.The effect of the temperature history was considered indirectly by taking into account the difference between the yield stress and the preconsolidation stress.The presented model was validated by comparing the predicted values with the experimental data in this paper and some published literatures.