A model for regular desiccation cracks formation

Abstract

A desiccation theory is developed providing a rational framework for a three-dimensional analysis of shrinkage and crack formation in a stiff clay surface layer. With the present model, we are estimating the shrinkage stress and the chemical potential variation in a morpheme produced after cracking, in a stiff clay surface layer, in terms of measurable quantities. In regular shrinkage morphemes, the shrinkage stresses are calculated from the shrinkage displacement and moisture content change. Other parameters such as the water mobility are introduced in order to express the chemical potential and the entropy changes in terms of the moisture content change and temperature at various instants of time. List of symbolsA Elemental section of an area exposed by a new crack a Coefficient E Young's modulus e Linear strain G Critical strain energy released rate h Interstitial fluid pressure h o Constant of integration J a T Desorbed flux of water K (= P h /P v ) Coefficient of lateral stress L Major diameter of a soil column formed after cracking (assumed elliptical) L c T Wave length of maximum shrinkage m w Mass of water M a T Water transportivity coefficient N Normal on the external surface P h , P v Lateral and vertical force driving shrinkage P i j Direct shear forces driving shrinkage r Internal radius of the morpheme

Modeling soil desiccation cracking by analytical and numerical approaches

“…The field and laboratory experiments are used to study the morphology, geometry and development of the desiccation cracks, and the effect of some parameters (eg specimen dimensions, boundary conditions, soil properties, and drying condition) on their formation. The theoretical methods aim to predict the desiccation cracks geometry (depth and spacing between cracks). The numerical approaches are introduced to simulate the formation and propagation of cracks during desiccation or to characterize material properties that cannot be easily measured in laboratory because inaccessible.…”