TITLE:
Characterizing Dessication Cracking of a Remolded Clay (Eutric Vertisol) Using the Fractal Dimension Approach
AUTHORS:
David Lomeling, Mandlena C. Kenyi, Modi A. Lodiong, Moti S. Kenyi, George M. Silvestro, Juma L. L. Yieb
KEYWORDS:
Fractal Dimension, Filtering, Thinning, Critical SMC, Dessication, Crack Intensity Factor
JOURNAL NAME:
Open Journal of Soil Science,
Vol.6 No.4,
April
21,
2016
ABSTRACT: Fractal
dimension fd, was used as one of the
parameters to describe dessicationcracking 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 r2 = 0.247 (P fd with SMC was best described using a
polynomial function at r2 = 0.969 (P 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.