Infiltrations in an unsaturated compacted barrier clay

Measurements of the unsaturated permeability coefficient versus the degree of saturation have been performed on a clay compacted in the Standard Proctor conditions. The experimental device used is an infiltration column with 50 mm in diameter and 220 mm in height. Unsteady state flow with controlled pressure is applied using a GDS pressure-volume controller. The interpretation of the instantaneous hydric profiles thus obtained highlights the exponential variation of the water permeability coefficient when the degree of saturation exceeds 0.75. In addition, drying and wetting tests were performed on samples prepared in various initial states, which makes it possible to deduce the relative permeabilities indirectly. Numerical modelling of hydraulic conductivity using Fredlund and Xing (1994) model was carried out. One observes a good agreement in the description of the relative permeability curves in the [S-r, K-r] and [-u(w), K-r] coordinates systems.