This paper concerns the determination of the soil permeability from water tests performed in the proximity of a partially saturated layer. The objective of the study is the determination of the influence of the presence of a partially saturated zone on the shape factor. The latter is a key parameter for the interpretation of soil permeability from in situ tests. The paper is composed of three parts. The first part describes the water test generally used in the measurement of the permeability in saturated soils, and we discuss difficulties of its use in the presence of unsaturated soils. The second part includes the numerical model used to study the flow of water in partially saturated soils. The last part involves a study of the influence of the presence of a partially saturated soil on the interpretation of the water test.
