Review of factors affecting formation of cracks in clay layers

Clays exhibit volumetric changes when exposed to different environmental conditions. Particularly desiccation process in clays produces vertical settlements and cracks can appear as a consequence of shrinkage. The mechanisms in which the environment, the soil properties, and the geometric configuration as a whole affect cracking characteristics are not yet understood; even if numerous experimental tests have been realized in thin layers of clay to evaluate the influence of different variables. Variables studied in abundant research include the effect of: air temperature, thickness of soil layer, bottom surface material, and tensile strength. The aim of this paper is to present a review of the experimental results made by different researchers, highlighting their main contributions, and relevant aspects for future works.