红黏土平面裂纹扩展的分形特征

Fractal characteristics of plane crack propagation of red clay

为了探讨红黏土在失水过程中裂隙的演化规律,进而为确定红黏土的力学参数提供理论支持,通过采集红黏土在失水过程中不同时刻表面裂隙扩展状态的数字图像,并采用MATLAB软件对图像进行滤波、阈值分割后获得裂纹演化的二值图。在裂纹演化二值图的基础上,计算红黏土表面裂隙的简单分形维数、裂隙率以及多重分形谱与失水量之间的关系。结果表明:裂纹演化二值图的分形维数以及裂隙率与失水量之间有很好的线性关系,其多重分形谱曲线形状以及谱宽表能够很好表述红黏土平面裂纹演化在分形结构上不均匀分布的性质。

The evolution law of fracture of red clay in the dehydration process is discussed to provide theoretical support for determining the mechanical parameters of red clay.By collecting the digital images of surface crack propagation of red clay at different times in the dehydration process,the binary image of crack evolution can be obtained after filtering and threshold segmentation by using MATLAB software.On the basis of the binary image of crack evolution,the relationship among the simple fractal dimension of the surface crack of red clay,the fracture rate,multi-fractal spectrum and the quantity of water loss are analyzed.The results show that the fractal dimension of the binary image of crack evolution,the fracture rate and the quantity of water loss have a good linear relationship;the curve shape of the multi-fractal spectrum and the chart of spectral width can express the nature of uneven distribution of the surface crack evolution of red clay in the fractal structure.