FORMATION OF INHOMOGENEITY IN PORE SPACES IN HEAVY SWELLING SOILS UPON FREEZING-THAWING

A radioisotope technique for studying the variation in the total hydra ulic permeability over the area of soil samples with an unbroken compo sition was elaborated. This technique was applied to characterize the pore space of the soils upon their swelling and also upon freezing-tha wing. Upon freezing, the portion of the relatively large pores, mainly providing the filtration flux, were found to be considerably increase d. Such a redistribution of the pores over their size under the condit ions of the complete moisture-saturation of the samples and at their c onstant volume is related to ice segregation. After thawing, the obser ved internal stress relaxation is accompanied with a gradual decrease of the total hydraulic permeability and its dispersion over the surfac e area. The relaxation times, depending on the nature of ions in the p orous solution, were estimated for this process.