Fig. 1. Scheme of correspondence between a real layer and a model from Bronswijk (1988)(1989, 1990, 1991a, 1991b) (vertical cross-sections). (a) The real connected layer of thickness z with distributed cracks. Initial saturated state at the gravimetric water content w = w_o. (b) Model layer of disconnected cubes of size z without cracks at w = w_o. (c) Real subsidence z of the layer and the same cracks after drying to w < w_o and opening (openings are symbolized by thicker lines; additional developing cracks are not shown). (d) Model layer after drying to w < w_o. All cracks are concentrated as gaps (shaded strips) between shrinking parallelepipeds of horizontal size x' without cracks. Subsidence of the disconnected parallelepipeds, z' < z.