Drying shrinkage of deformable porous media: Mechanisms induced by the fluid removal

Mechanisms of free shrinkage strains of desiccating deformable porous media are studied. The roles of surface evaporation rate, surface tension, and viscosity of pore fluid, soil compressibility and permeability are investigated. For drying tests on two geomaterials with three different pore fluids the evolution of shrinkage strain and fluid content is reported. Most of the strains occur in the saturated phase of drying prior to cracking. Simulations of this phase include evaporative fluxes at the external surfaces, a consequent water transport across the sample toward the surface producing pore pressure and stress gradients, local water content change, and deformation. Biot theory is used.