Intrinsic Sorptivity and Water Infiltration into Dry Soil at Different Degrees of Saturation

The sorptivity S quantifies the effect of capillarity on liquid movement in a porous material. For liquid infiltration into an initially dry material, S is a parameter that is contingent on both liquid and material properties as well as the maximum liquid content behind the infiltrating front, θm. In prior work, Culligan et al. (2005) used scaling analyses to derive a dimensionless, intrinsic sorptivity S that is constant for different liquids, Miller-similar materials and differing values of Se(av) •, the average degree of saturation behind the infiltrating front. The validity of the dimensionless S, and an accompanying dimensionless Boltzmann transformation Φ, was tested for different liquids by examining the horizontal infiltration profiles of water and Soltrol 220 in uniform dry sand at a constant Se(av) = 0.79. This work extends the validity testing of S * and Φ to conditions of varying Se(av). Twenty-one distilled water horizontal infiltration experiments, with a range 0.64 • Se(av) • 0.86, were preformed in uniform dry sand packed at an average porosity n = 0.36. The results of the tests indicate an intrinsic sorptivity value of 0.121, which compares well with the value of Sav * = 0.128 reported by Culligan et al. The work also confirms that the dimensionless Boltzmann transformation Φ can be used to generate a similarity profile for moisture content, even when infiltration takes place under different degrees of saturation.