ABSTRACT
When natural and engineered systems are subjected to shrinkage, driven by cooling or drying, the resulting stresses may lead to the formation of fractures. Experimental studies of this phenomenon and fracture spacing theory show that the spacing between fractures initially decreases as extensional strain increases in the direction perpendicular to the fractures. At a certain ratio of spacing to layer thickness, however, no new fractures form and the additional strain is accommodated by the further opening of existing fractures: the spacing then simply scales with layer thickness. In field and laboratory observations, two kinds of fracture patterns are commonly observed-parallel fractures (Figure 20.1a) and polygonal fractures (Figure 20.1b).
