Shrinkage development during soil desiccation

Clayey soils undergo shrinkage during desiccation. When shrinkage is restrained by the boundary conditions or by internal stresses, tensile stresses are generated within the soil body. These stresses eventually produce tension crackswhich create problematic situations in many engineering applications. Presence of shrinkage cracks is significant in many applications such as earth embankments, landfill clay liners, foundations, and road pavements. Desiccation or thermally induced induced shrinkage cracks cause problems in other disciplines as well, for example in mining engineering, agricultural engineering and materials engineering. It is important to understand the shrinking behavior of soil in order to study the desiccation crack development in clayey soils. Free shrinkage of slurry clay was observed in laboratory experiments. Image analysis, along with Particle Image Velocimetry (PIV) technique was used to analyze the data obtained. Relatively small specimens 100 mm longwere used so that strains could be measured to high accuracy.Werribee clay, an expansive clay found in West Melbourne, was used in the experiments. Basic clay properties include liquid limit of 127%, plasticity index of 101 and linear shrinkage of 22%. This paper discusses the relationship between strains (vertical, horizontal, and volumetric), displacements, water content, degree of saturation and void ratio. Shrinkage strain development prior to crack initiation was examined to identify crack failure condition