Simple method to determine coefficient of permeability of unsaturated soil

This study introduces a novel transient method for determining the unsaturated coefficient of soil permeability, requiring the measurement of volumetric water content and corresponding pore-water pressures at three distinct points. This distinctive advantage of the method lies in eliminating the need to measure or control the flux at any point within the soil profile. The proposed method was validated through numerical simulations that performed one-dimensional seepage analysis, followed by a comparison of the calculated unsaturated coefficients of permeability with the input data. The strong agreement between the compared results validates the feasibility of the proposed method for determining the unsaturated coefficient of soil permeability. Moreover, a spatial interval of less than 5 cm is recommended to ensure accurate results for the unsaturated coefficient of permeability when employing this method.