Simplified approach to the behavior of compacted soils on drying and wetting paths

The paper describes the drying and wetting paths of two soils, compacted to Proctor optimum water content and maximum density, compared to those of the same soils prepared as slurries. In the [log(u_c), e] and [log(u_c), w] coordinate systems, these paths can be modelled by 2 straight lines starting from the compaction point, the parameters of which are correlated with the liquid limit. In the second part of the paper, two expressions are proposed to extend the effective stress concept to unsaturated soils, one based on a micromechanical model, the other one on thermodynamical considerations. The use of these expressions to interpret data from literature leads to a unique failure criterion for both saturated and unsaturated soils. Both approaches provide simple analysis methods for practicing engineers.