Abstract
A convenient method of test for permeability of unsaturated soil under controlled air pressure was examined. It was reflected on the improvement of procedure to measure a little rate of discharge infiltrated, headloss of filters attached to soil sample and so on. As a result, a guide to select filter in consideration of permeability of soil was obtained, and water content distributed through soil column was verified to be approximately uniform. It was also found that a fairly great value of hydraulic gradient was allowable to be burdened to sample, and that degree of saturation could be controlled corresponding to the air pressure, which made operation time shorter than in the previous procedure.