Abstract:
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It is difficult to formulate a general model to capture cracking initiation and evolution, because there are multiple factors that influence these processes. In order to simplify the evaluation and get more insight on the phenomenon, a series of shrinkage tests were performed inducing one-dimensional primary cracking on remolded clay from Bogotá. The results allowed the proposal of a conceptual model that, based on mould shape factor, initial moisture content and evaporation rate, may predict time for crack initiation and identify the location and direction of primary and secondary cracks. Results indicate that boundary conditions play a significant role in cracking evolution, due to the restrictions imposed to the free shrinkage and to the homogeneous evaporation rate. The moulds used for soil desiccation, allowed the induction of predefined cracks when their shape factor values were greater than 1.5. In these cases the model is simple and may be considered as a model of cracking with one degree of freedom. When moulds have a shape factor between 1 and 1.5, the degrees of freedom increase dramatically leading to much more complex crack patterns. |