Effective stresses in unsaturated soils after freezing and thawing

In seasonally frozen areas, it is fully realized for environmental problem that frost heave, freezing and thawing gives damages to civil engineering structure. It has been known that freezing and thawing make volume change due to frost heave and decrease of shear strength in soils. It is necessary to approach for engineering properties of unsaturated soils subjected to freezing and thawing. This study aims to make clear the influence of degree of saturation, dry density of index properties to the mechanisum of frost phenomena in unsaturated soils. Also, in consideration of the effective stress principle in unsaturated soils, it is described relation between the suction pressure, volume change and decrease of shear strength in unsaturated soils.