Permeability and volume changes in till due to cyclic freeze/thaw

Abstract

A fine-grained nonplastic till was compacted in the laboratory in three types of rigid wall permeameters, having a volume of 0.4, 1.5, and 25 dm3, respectively, and, was thereafter exposed to a maximum of 18 freezing and thawing cycles. The permeabilities in the vertical direction of saturated samples were measured in unfrozen soil as well as in thawed soil. The results show that the permeabilities changed after freezing and thawing. The magnitude of the changes in this study were in the range 0.02-10 times after freeze/thaw compared with the unfrozen soil. Soil exhibited volume changes subsequent to freeze/thaw. The volume typically decreased for an initially loose soil and increased for a dense soil. Independent of whether the initial soil structure was loose or dense, a constant "residual" void ratio, eres, was obtained after 1-3 cycles. For the soil investigated, the residual void ratio ranged from 0.31 to 0.40.Key words: till, fine-grained, non plastic, permeability, freeze/thaw, residual void ratio.