Evaluation of the Instantaneous Profile Method for the Determination of the Relative Permeability Function

Abstract

Experimental determination of water permeability in unsaturated conditions is a critical issue. Among the existing experimental techniques, the instantaneous profile method is frequently used. When applied to bentonite-based materials, the method often shows that the water permeability-suction function significantly differs depending on the distance from the wetting face. Such behaviour has been interpreted as a consequence of structural changes in the sample which directly affect the water flow properties. In order to better understand the involved processes, a hydromechanical simulation of an infiltration test is performed. While structural changes are shown to affect the hydraulic properties, the computed water permeability-suction evolution is strongly affected by the interpretation of the raw experimental data.