Fig. A2.1. Two-dimensional illustration of the analogy between the three-dimensional shrinkage of a layer and a sample of an arbitrary shape. (a) The current specific volume of a layer with dotted initial upper surface (corresponding to _l = = _o) is equal to the current specific volume () of a soil matrix (shaded area) plus the current specific crack volume (_cr.l) (black strips; vertical cracks are only shown for simplicity). , _o, and _l are connected by Eq. [A2.1]. (b) The current specific volume (_s) of a sample of an arbitrary shape with dotted initial surface (corresponding to _s = = _o) is equal to the current specific volume () of a soil matrix (shaded area) plus the current specific crack volume (_cr.s) (black strips). , _o, and _s are connected by Eq.[A2.2], which is similar to Eq.[A2.1]. The M factor is the generalization of the r_s factor for a sample of an arbitrary shape.