Permeability Test for Unsaturated Soil

A method has been developed for measuring the hydraulic conductivity of unsaturated soil using the instantaneous profile method and a combination of thermocouple psychrometers and tensionmeters. Soil samples are first compacted or trimmed into tubes. The tubes are instrumented with psychrometers, and the soil is slowly moistened from one end. When the unsaturated soil becomes too moist for psychrometers to function properly, the psychrometers are removed and tensiometers are inserted. Equipment, procedures, and results for two soils are described. The method has broad range and good versatility, but testing times are long and equipment costs are significant. (Author)