An empirical stochastic model for the geometry of two-dimensional crack growth in soil (with Discussion)

A model is presented for the fragmentation of drying soil, based on the geometry of two-dimensional crack growth. The model restricts itself to the formation of two-dimensional cracks. The pertinent parameters used to generate cracking patterns include those used to characterise crack growth development as a random walk, fragmentation of peds above a certain size threshold and attraction of cracks within defined distances. A sensitivity analysis is carried out to examine the effect of varying these parameters on final cracking patterns. The variation of curvature and threshold to aggregate splitting are shown to have significant effects. Simulations based on this model are illustrated, and compared with cracks in real soil.