DESICCATION OF A SENSITIVE DAY - APPLICATION OF THE MODEL CRACK

Field data obtained during the desiccation of an intact clay were used to assess the performance of a model enabling the prediction of depth and spacing of primary shrinkage cracks. The model requires several i nput parameters such as the soil-water characteristic curve to predict the evolution of the suction profile with time, the tensile strength of the soil to define the conditions at crack initiation, and the frac ture toughness to calculate ultimate crack depth, Predictions of sucti ons at crack initiation, time of crack initiation, and depth of crack propagation were reasonable using laboratory determined values of thes e soil properties obtained from undisturbed samples. Field data sugges t that neighbouring cracks form where the computed relief stresses rea ch 80 to 88% of the tensile strength of the soil.