Multi-scale Study of Desiccation Shrinkage in Granular Soils

International audienceThis paper aims to identify and evaluate various critical mechanisms associated with the processes of desiccation shrinkage in drying silty soils. A previously developed 1D bundle-of-tubes model is refined to simulate the various stages of drying shrinkage in 2D using the actual pore size distribution based on Mercury Intrusion Porosimetry (MIP) data. It is revealed that the resulting shrinkage evolution is affected by air entry that may occur in two possible scenarios: air incursion at the external surface and formation of vapor nucleus in the interior. The analysis of mechanical deformation is coupled with the numerical simulation of the drying process which can be often characterized as a two-stage development, consisting of a constant rate period and a falling rate period. Numerical simulation of the drying rate evolution suggests that it may be closely associated with the onset of air entry and/or the progress of desaturation. Further transition of solid-water structural configuration into funicular and pendular states from initially capillary state is simulated