Influence of the unsaturated zone of soil layer on the solute migration

摘要

It is recognized that the sealing layer which must limit the flux of pollutants must be qualified by its coefficient of permeability. But the thickness and the saturation state of the liner are never evaluated. With our infiltration tests and TDR measurements it is shown that the layer thickness takes part in pollutant transfer reduction. The two earth materials used show that the difference of the solute migration concerns also the capability of the soil to retain the solute. The electrical conductivity profiles prove that during the soil saturation the migration mode change. The soil saturation process delays the solute movement even the coefficient of permeability is higher than 10~(-9)m/s. The time need to reach the retention depend on the type of soil and especially the compaction dry bulk density. This time value can be used to evaluate the soil layer efficiency.