Abstract
This paper describes characteristics of air permeability of unsaturated soils. The method of air permeability test which is able to control the suction repetitively to adjust the degree of saturation of an unsaturated soil sample is proposed. The relationships among air permeability coefficient, degree of saturation and suction are evaluated. As a result, it made clear that air permeability coefficient in the range from 10-3cm/s to 100cm/s was able to be measured by the proposed method. And then, it was recognized that the relationships between air permeability coefficient, degree of saturation and suction showed hysteresis in drying and wetting processes, and that the air permeability coefficient in wetting process was larger than the one in drying process.
