Experimental Techniques for the Study of the Cracking Mechanisms in Drying Clays

International audience; Desiccation cracking in drying clays is a common problem with a severe impact on the performance of clayey soils in various geotechnical engineering applications. This article highlights different methods to analyze the formation and propagation of cracks related to desiccation in clays. The research is based on an experimental study of different clays subjected to drying and a phenomenological study of cracking during free desiccation tests on thin clay layers. The approach consists, on one hand, in analyzing the characteristics of cracks with the Image-J software and, on the other hand, in determining the local two-dimensional strains and displacements fields using the digital image correlation (DIC) method. Various tests were carried out to verify the accuracy of the DIC method. Plotting the mechanical strain tensors results in a better understanding of the drying mechanisms of the studied clays. The results show that the combination of two image processing methods, associated to fracture mechanics, is a powerful tool to investigate the mechanisms of cracking in drying soils.