Estimation of the air permeability function from the Soil-Water Characteristic Curve

The multiphase flow (including liquid flow and air flow) in unsaturated soil is related to many engineering problems such as contaminant transport, rainwater infiltration and soil-water evaporation. It is proven that water flow in unsaturated soil can be estimated using the concept of pore-size distribution function. Many models have been proposed to estimate the water flow or water permeability function, kw, from soil-water characteristic curve (SWCC). On the other hand, a limited model has been proposed to estimate the air flow or air permeability function, ka, from SWCC. Most of the models used for the estimation of the air permeability functions are empirical and they are dependent on the empirical parameters. In this paper, the relative air coefficient of permeability was estimated using the concept of pore-size distribution function. In the method proposed in this paper, there was no empirical parameters adopted and the estimation results purely depended on the soil-water characteristic curve. The proposed method was verified against experimental data from published literature.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author