多重干湿循环下的土壤裂缝网络几何与分形特征

发布时间：2018-05-11 10:31

本文选题：干湿循环 + 裂缝网络　；参考：《节水灌溉》2017年06期

【摘要】：通过室内试验研究了多次干湿循环下土壤干缩裂缝开闭规律,采用数字图像处理技术与Matlab测量功能,分析了不同含水率下土壤裂缝网络几何与分形特征,旨在研究干湿循环过程中裂缝形态特征、其网络复杂性及自相似性变化规律。结果表明,在干湿循环作用下,裂缝稳定时的土壤裂缝面积率和平均宽度逐渐减小,干湿循环对裂缝的作用效果随着循环次数的增加而减弱;稳定状态下的裂缝骨架长度几乎不受影响,且在裂缝发育过程中其长度较面积率、平均宽度提前到达稳定状态,表明裂缝发育后期主要以宽度增长为主;裂缝网络连通性增强,于第3次干湿循环后趋于稳定。首次干燥过程中裂缝网络分形特征曲线比受干湿循环作用后平滑,土壤经历干湿循环后,形成裂缝骨架网络时所对应的含水率提前,而稳定状态下的裂缝网络分形维数随着干湿循环次数增加呈递减的趋势。
[Abstract]:The opening and closing laws of soil dry-shrinkage cracks under repeated dry-wet cycles were studied through laboratory experiments. The geometry and fractal characteristics of soil cracks network under different moisture content were analyzed by using digital image processing technology and Matlab measurement function. The purpose of this paper is to study the characteristics of fracture morphology, the network complexity and the variation of self-similarity during dry-wet cycle. The results showed that under the action of dry and wet cycles, the area rate and average width of soil cracks decreased gradually when the cracks were stabilized, and the effect of dry and wet cycles on cracks decreased with the increase of cycle times. In the process of fracture development, the length of fracture skeleton is almost unaffected, and the average width reaches the stable state earlier than the area ratio in the process of fracture development, which indicates that the width of fracture is mainly increased in the later stage of fracture development, and the connectivity of fracture network is enhanced. It tends to be stable after the third wet and dry cycle. In the first drying process, the fractal characteristic curve of crack network is smoother than that of dry and wet cycle, and the moisture content corresponding to the formation of crack skeleton network is earlier than that of soil after dry-wet cycle. The fractal dimension of fracture network decreases with the increase of dry-wet cycle times.
【作者单位】：河海大学南方地区高效灌排与农业水土环境教育部重点实验室;河海大学水利水电学院;
【基金】：国家自然科学基金资助项目(51579069);国家自然科学基金资助项目(51179050)
【分类号】：S152

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