Numerical Analysis of Drying Cracks Developed Under Field Conditions

Abstract

Naturally occurring soils exhibit swelling and shrinking behavior induced by moisture changes. For example, soils tend to swell upon wetting and shrink during drying. This behavior leads to stresses changes that may exceed the soil strength leading to crack formation, which may in turn close during infiltration phases when the soil becomes wetter and expands. Several geotechnical engineering problems, such as foundations and embankments, are strongly affected by the presence of cracks. The study of crack formation and propagation in porous media is a very complex problem and possesses several challenges. Fracture propagation in this research will be modeled using the mesh fragmentation technique (MFT), which consists in introducing finite elements (FE) with high aspect ratio in between the standard (bulk) elements of the FE mesh. In this dissertation, the Saint-Alban clay excavation-drying case is studied in details and used to validate the MFT. The test site is located in Saint-Alban, 80 km west of Québec City in the Saint Lawrence Valley. Numerical simulations were performed in order to achieve a better understanding of the phenomena behind the formation and propagation of desiccation cracks in soils under natural conditions.