Thickness effect on crack evolution of expansive soil
LUO Zhao gang1, WANG Shi ji1,2, ZHANG Ji wei1, YANG Zhen bei1
1. College of Engineering and Technology, Southwest University, Chongqing 400715, China; 2. School of Civil and Architectural Engineering, Yangtze Normal University, Chongqing 408100, China
Abstract:The crack development of expansive soil is affected by many factors, including soil properties, environmental conditions, boundary conditions and soil sizes. Crack evolution is greatly influenced by thickness. In order to explore the specific influence rules of the thickess in the whole process of water loss shrinkage and cracking of expansive soil, four large-diameter circular mud samples with different thicknesses are prepared in the experiment. With the help of image processing technology, the dynamic change relationship of the basic crack indexes with the decrease of water content are quantitatively analyzed by recording the evolution process of cracks in the samples. The experimental results show that the process of water loss shrinkage and crack expansion of expansive soil are significantly affected by the thickness. The crack of the sample with smaller thickness is fully developed, and it is long and thin. However, the sample with larger thickness has a single wide crack and is affected by obvious boundary effect. The development of the cracks is preliminarily estimated by the ratio of thickness to diameter. In addition, the morphology and distribution of the cracks can be characterized effectively by combining the fractal dimensions of area and length. The fractal dimension of crack length is generally about 1~1.5, while the surface integral dimension is basically maintained at 1.6~1.7. Moreover, based on the tensile failure theory of soil cracking and the shrinkage and evaporation of the samples, the difference of soil cracking affected by the thickness is theoretically analyzed, and the expansion rules of cracks are further explored.
骆赵刚, 汪时机, 张继伟, 杨振北. 膨胀土裂隙发育的厚度效应试验研究[J]. 岩土工程学报, 2020, 42(10): 1922-1930.
LUO Zhao gang, WANG Shi ji, ZHANG Ji wei, YANG Zhen bei. Thickness effect on crack evolution of expansive soil. Chinese J. Geot. Eng., 2020, 42(10): 1922-1930.
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