Estimating Air-Water Hydraulic Conductivity Using Soil-Water Characteristic Curve

Geotechnical engineers frequently encounter environmental problems involving unsaturated soil. Geotechnical problems related to hydraulic conductivity are affected by both air flow and water flow. Decision of coefficient of permeability for each of air flow and water flow has increased significantly. In this study, the air-water permeability testing apparatus is modified for determining hydraulic conductivity of double fluid flow. The soil-water characteristic curve of sand-clay mixture soil was determined by desorption using high air entry disk and glass desiccator. Vapor pressure technique to control relative humidity environment is effective for determining the water content in high soil suction. Soil-water characteristic curve can be used for interpretation of hydraulic conductivity. The coefficient of air permeability is greater than that of water in unsaturated sand-clay mixture soil.