中文摘要：

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。

英文摘要：

In order to investigate soil geometric characteristic, complexity of network and self similarity regularity in drying-wetting cycle process, laboratory tests were carried out to study the propagation and the closure law under multiple drying-wetting cycles by using the technology of digital image processing and Matlab measurement function to analyze soil crack network geometric and fractal characteristics in the different moisture content. The results show that under the effect of drying-wetting process, the crack area rate and mean width decreases when soil crack is stable; the effect of drying-wetting circulation on the crack decreases with the increase of the cycle frequency; the crack skeleton length under steady state is almost not affected; in the development process of the crack, the length reached a steady state in ad- vance before area ratio, and average width, which means that crack width growth is the main aspects in the late development stage; the increase of the connectivity of fracture network tend to be stable at the third time after drying-wetting cycles. The fractal characteristic of crack network for the first time in the drying process curve is smoother than that by the effect of drying-wetting. After wetting-drying cycles, the moisture content of the crack network is formed in advance, and the fractal dimension of the crack network in the steady state increases with the increase of the frequency of wetting-drying cycles.