Effects of entrapped air bubbles on the mechanical behaviour of quasi-saturated soils

This paper presents a model on the hydromechanical behavior of quasi-saturated soils containing entrapped air bubbles, constituting a discontinuous gaseous phase. These air bubbles reduce the compressibility of pore fluid hence impact on the mechanical behavior, while the liquid-gas interface gives rise to menisci and hence possibly suction effects on the soil skeleton. In parallel, air can dissolve in water and then migrate through the porous space by water flow and by diffusion. In practical situations, different parts of a soil mass can be at different degrees of saturation; transition through different saturation regimes relative both to space and time is possibly. The presentation of a theoretical model recently developed by the authors, capable of simulating such continuous transition relative to space and time, is the objective of this paper. A limited numerical study will also be presented to show the consistency of this model.