粉煤灰颗粒图像处理及多重分形特征

陈玖颖，赵衡，赵明华

摘   要：为探究粉煤灰孔隙率计算方法及其孔隙多重分形特性，引入相似维数的概念推导其分形维数基本公式. 通过对试样制作模具进行加工以控制击实度，配制一定含水率的粉煤灰试样. 利用显微数码成像技术获取粉煤灰试样中孔隙和颗粒的直径、数量. 选定4个不同深度截面及两个剖面的上下端作为观测面，借助体式显微镜进行不同倍数下的成像，以分析三维空间范围内的孔隙率变化规律;采用专业图像处理技术给出试样孔隙率. 研究结果表明，粉煤灰试验的孔隙率沿深度方向有减小趋势，幅值变化约为30%，且其孔隙分布具有明显的多重分形特征.

关键词：道路工程;粉煤灰;孔隙率;分形理论;图像处理

中图分类号：TU441                             文献标志码：A

Image Processing and Multi-fractal Characteristics of Fly Ash Particles

CHEN Jiuying，ZHAO Heng？覮，ZHAO Minghua

（College of Civil Engineering，Hunan University，Changsha 410082，China）

Abstract：In order to explore the calculation method of porosity and pore multi-fractal characteristics of fly ash，the concept of similar dimension is introduced to derive the basic formula of fractal dimension. By processing the sample mold to control the degree of compaction，a fly ash sample with a certain moisture content is configured. Secondly，the diameter and number of pores and particles in the fly ash sample are obtained by using digital microscopic imaging technology，and then the histogram of pores and particles can be obtained. Then 4 different depth sections  are selected，whose upper and lower ends are used as the observation surface，and photos at different magnifications are taken with the help of a stereo microscope to analyze the distribution of the pore area ratio in the three-dimensional space;finally，professional image processing is used. The technique gives the porosity of the sample and compares it with the measured results. The research results show that the pore area ratio of the fly ash has a decreasing trend along the depth direction，the variation of which would be about 30%，and its pore distribution has obvious multifractal characteristics.

Key words：road engineering;fly ash;porosity;fractal theory;image processing

粉煤灰是一種燃料燃烧所产生烟气灰分中的细微固体颗粒物，如燃煤电厂排放的工业固体废渣，其主要组成成分为二氧化硅、氧化铝和氧化铁等. 低热量燃煤的扩大利用以及除灰效果的提高，导致粉煤灰排放量大幅增长，出于环境保护的需要及粉煤灰的贮放需求，开拓粉煤灰的用途显得刻不容缓. 粉煤灰具有球形颗粒特征，组织疏松，渗透性良好，因而被广泛应用于路堤填筑[1-4].

粉煤灰的渗透性对路堤的压实度和稳定性等力学性能起到关键影响作用[5-6]，而粉煤灰的渗透性又主要取决于孔隙率的大小，因而研究粉煤灰的孔隙率及渗透性等对粉煤灰路基填筑的工……