A Simplified Analytical Model for Desiccation Cracking of Clay Layers in Laboratory Tests

Abstract

This paper presents a simplified analytical model for desiccation cracking of clay layers in laboratory tests. An analytical solution is presented for the maximum tensile stress developed at the mid section of the layer. As the desiccation progresses, the clay layer will crack at the middle when the maximum tensile stress exceeds the tensile strength of the clay. For further desiccation, the analytical solution is recursively applied to model the subsequent subdivision of the clay layer through formation of secondary and tertiary cracks. The model was applied to predict the laboratory desiccation tests of long-thin clay layers that produced parallel cracking. The non-linear material properties of clay and the basal interface were represented by empirical correlations with the moisture content. The free shrinkage strain was found to be linearly correlated to moisture content reduction. The model was able to predict the development of cracks during desiccation reasonably well. In particular, it was highlighted that once a crack initiates, subsequent subdivision of the layer takes place rather rapidly until a number of cracks that is in equilibrium with the test conditions has emerged.