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

作　　者：David Lomeling Mandlena C. Kenyi Modi A. Lodiong Moti S. Kenyi George M. Silvestro Juma L. L. Yieb David Lomeling;Mandlena C. Kenyi;Modi A. Lodiong;Moti S. Kenyi;George M. Silvestro;Juma L. L. Yieb(Department of Agricultural Sciences, College of Natural Resources and Environmental Studies (CNRES), University of Juba, Juba, South Sudan)

机构地区：[1]Department of Agricultural Sciences, College of Natural Resources and Environmental Studies (CNRES), University of Juba, Juba, South Sudan

出　　处：《Open Journal of Soil Science》2016年第4期68-80,共13页土壤科学期刊（英文）

摘　　要：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.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.

关 键 词：Fractal Dimension FILTERING THINNING Critical SMC Dessication Crack Intensity Factor 

分 类 号：P59[天文地球—地球化学]