Hydraulic conductivity of kaolinite-silt mixtures subjected to closed-system freezing and thaw consolidation

Kaolinite-silt mixtures at different clay contents were subjected to closed-system freezing and thaw consolidation to obtain data on the hydraulic conductivity of thawed samples. A simplified void ratio model was developed based on the compressibility characteristics of the clay aggregates and the freezing-induced suctions. The close agreement between predictions and observations suggests that the assumptions of the model are reasonable, especially that maximum freezing-induced suctions developed in the clay aggregates are related to the temperature at which no significant change in unfrozen water content occurs rather than the actual freezing temperature. Furthermore, the compression characteristics of thawed mixtures is essentially controlled by the recompression of the clay aggregates in the overconsolidated domain. The void ratio model is linked to a permeability model that suggests that the hydraulic conductivity of thawed mixtures can be defined by a reference value of the unfrozen soil and a parameter specific to each mixture.