Characterizing Dessication Cracking of a Remolded Clay (<i>Eutric Vertisol</i>) Using the Fractal Dimension Approach

Abstract

Fractal dimension fd, was used as one of the parameters to describe dessication cracking pattern of a remolded Black Cotton soil (Eutric Vertisol). The fractal dimension computed from filtered, thinned and skeletonized binary images of soil cracks using the Fractal3 software provided an insight into temporal variability of fd as well as its relationship with the Crack Intensity Factor (CIF) and Soil Moisture Content (SMC). The results showed that even for single crack, the fd prior to filtering and thinning were higher than after. Cracking patterns were observedfroma chosen soil sample during dessication and the corresponding relationship between fd and CIF compared and monitored. As the critical SMC decreased during drying (45% to 27%), the CIF soil increased (0.023% -5.75%), so did the fd (1.233 to 1.7193). The fd showed a positive linear correlation with CIF at r 2 = 0.247 (P < 0.05) whereas the correlation of fd with SMC was best described using a polynomial function at r 2 = 0.969 (P < 0.05). The fd was sensitive to dessication cracking and therefore on SMC changes. Visual observation of dessication cracking showed that CIF increased and attained stability after day 4 while the computed and logarithmic transformed crack area attained stability between days 7 to 10 gradually decreasing to values below 2%. The estimated crack Cover or Brightness of the digitized binary images also gave better approximation of the CIF though this was slightly higher. Our results showed that dessication cracking of the Eutric Vertisol was independent of antecedent critical SMC and was time-constrained. Further soil cracking therefore stopped once maximum CIF was attained and only widening and deepening of pre-existing cracks continued.

A First Insight on the Interaction between Desiccation Cracking and Water Transfer in a Luvisol of Belgium

“…The samples were prepared from a rectangular steel box of 25 cm length × 20 cm width × 1.6 cm height or thickness (Figure 1). The thickness was chosen to enhance the drying-induced cracking process according to the literature and the pretesting experiment [5,20]. The undisturbed samples (NDS = RTRI and CTRO) were saturated with distilled water from the bottom by a capillary rise for 24 h before the commencement of the experiment.…”

“…This requires that researchers include a dynamical analysis of cracks in parallel to a soil hydrodynamical assessment [19]. However, due to crack complexity in form, size, configuration and distribution, crack analysis is often neglected in soil hydrology research, especially as agricultural science is concerned [7,20].…”

Effects of tire chips on the shrinkage and cracking characteristics of clayey soils

“…Desiccation cracking may be perceived as a two-fold process that entails a gradual loss of moisture from an initially saturated porous body. 1 It is commonly known that desiccation clay soils crack when the tensile stress develops in the soil due to the matric-soil suction exceeding the tensile strength of the soil. Tensile stresses only develop when the soil is, in some way, restrained against shrinkage.…”