Physical modelling of freezing and thawing of unsaturated soils

Increasing interest in the development of thermo-hydro-mechanical numerical models has heightened the need for results from fully instrumented physical models that present the evolution of the soil properties during freezing and thawing. This paper presents a set of results from a physical model of freezing/thawing cycles of unsaturated soils to improve the state of the art regarding moisture transport in soils. The physical model that was developed used a set of measuring devices, which included a gamma-ray densitometer, temperature transducers, tensiometers, capacitive moisture transducers and displacement sensors. These sensors allow measurement of the evolution of ice content, unfrozen water content, temperature, pore water pressure and dry density. Fine sand and silt in initially unsaturated states were used in the study. These soils were successively submitted to capillary rise and two cycles of freezing and thawing.