EFFECTS OF FREEZE-THAW CYCLES ON PROPERTIES OF SENSITIVE CLAY

A laboratory study of the evolution of the behaviour of a sensitive clay under many freeze-thaw cycles is presented; it follows the laboratory study of Leroueil et al. (1991) and the field study of Roy et al. (1992). The physical properties of the clay have been followed by means of consistency and permeability tests after each freeze-thaw cycle, and the mechanical behaviour has been assessed by means of falling cone, oedometer, and consolidated isotropically undrained triaxial tests. The changes in internal structure have been observed by means of the scanning electron microscope and the mercury porosimeter. The results show that the changes in properties are significant during the first three freeze-thaw cycles and hardly significant during the following cycles. The structure change can be explained by the high suction that develops during the generation of ice lenses behind the frost front.