基于SEM图片的钙质砂连通孔隙分析

发布时间：2019-05-24 06:05

【摘要】：钙质砂是一种以碳酸钙为主要成分的特殊砂土,由于在形成过程中保留了原生物的骨架,故钙质砂颗粒不仅形状各异而且富含孔隙。颗粒孔隙的存在对钙质砂的压缩、剪切、强度和破碎性等力学性质有很大影响。针对这一问题,取南海一处岛礁建设地基的钙质砂试样,根据粒径大小将其分为6个不同的粒组,在每个粒组中选出不同形状的代表性颗粒,对其进行电镜扫描试验。借助MATLAB图像处理程序,选取合适的阈值对扫描试验得到的图片进行二值化处理,对钙质砂的连通孔隙进行了分析,系统的研究了不同粒径和粒形钙质砂颗粒的表观孔隙率的分布规律。结果表明:对于粒径小于1 mm的颗粒,面孔隙度随着粒径的增大而增大,不同形状颗粒面孔隙度差别不大;粒径超过1 mm后,面孔隙度随着粒径的增大而减小;条状颗粒面孔隙度最大而片状颗粒的面孔隙度最小。
[Abstract]:Calcareous sand is a kind of special sand with calcium carbonate as the main component. Because the skeleton of the original organism is retained in the process of formation, the calcium sand particles are not only in different shapes but also rich in pores. The existence of particle pores has great influence on the mechanical properties of calcareous sand, such as compression, shear, strength and fragmentation. In order to solve this problem, the calcareous sand samples of an island and reef construction foundation in the South China Sea were divided into six different particle groups according to the particle size. The representative particles of different shapes were selected in each grain group and the electron microscope scanning test was carried out. With the help of MATLAB image processing program, the appropriate threshold is selected to binarize the images obtained from the scanning test, and the connected pores of calcareous sand are analyzed. The distribution of apparent porosity of different particle sizes and grain-shaped calcareous sand particles was studied systematically. The results show that for particles with particle size less than 1 mm, the face gap increases with the increase of particle size, but there is no significant difference between different shapes of particles, and when the particle size exceeds 1 mm, the face gap decreases with the increase of particle size. The strip particles have the largest face gap and the flake particles have the smallest face gap.
【作者单位】：同济大学岩土及地下工程教育部重点实验室;同济大学地下建筑与工程系;上海理工大学土木工程系;
【基金】：国家自然科学基金项目(51579178)
【分类号】：TU441

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