钙质砂颗粒内孔隙三维表征  

Three-Dimensional Characterization of Inner Pores in Calcareous Sand Particles

作　　者：周博[1] 库泉 吕珂臻[2] 汪华斌[1] Zhou Bo;Ku Quan;Lü Kezhen;Wang Huabin(School of Civil Engineering and Mechanics,Huazhong University of Science and Technology,Wuhan 430074,China;Institute of Chemical Materials,China Academy of Engineering Physics,Mianyang 621900,China)

机构地区：[1]华中科技大学土木工程与力学学院,武汉430074 [2]中国工程物理研究院化工材料研究所,绵阳621000

出　　处：《天津大学学报（自然科学与工程技术版）》2019年第A01期41-48,共8页Journal of Tianjin University：Science and Technology

基　　金：国家自然科学基金资助项目(41877233);湖北省自然科学基金资助项目(ZRMS2018000134)

摘　　要：南海钙质砂颗粒形状复杂,颗粒棱角突出且面孔隙与内孔隙结构发达.为了准确表征钙质砂内孔隙三维形态,本文借助高精度X射线μCT扫描技术,得到钙质砂颗粒高精度断层图像.通过对原始CT扫描断层图像切割、除噪、二值化等一系列操作,重构得到钙质砂颗粒三维图像.由于钙质砂颗粒外形不规则,因此直接提取其内部孔隙较为困难,本文通过对钙质砂颗粒的三维图像进行三维闭合运算等一系列算法的处理,较好地重构了钙质砂内部的三维孔隙.根据块状钙质砂颗粒的外表特征、内孔隙孔隙率的大小、孔径分布曲线形状以及分形维数的大小,可以大致将块状钙质砂颗粒分为两种类型.第1种类型块状钙质砂颗粒外表存在较多沟壑且内孔隙较为发达,第2种类型块状钙质砂颗粒内孔隙较不发达且连通性较低.两种类型块状钙质砂颗粒内孔隙的孔隙率与孔径分布曲线存在明显差异.同时研究发现,钙质砂颗粒内孔隙较好地符合三维分形特征,且分形维数的大小与孔隙率大小成正相关关系.为了深入地研究钙质砂颗粒内部孔隙的连通性,本文通过计算其距离图获得颗粒内孔隙的空间网络模型,对其分析得出,钙质砂颗粒网络模型的配位数分布大体趋势相同,由于两种钙质砂颗粒内孔隙形态的差异,配位数的分布也略有差异.The shape of the calcareous sand particles found near the South China Sea is complex. The edges of these particles are prominent,and the surface pore and inner pore structures are developed. In order to accurately characterize the three-dimensional (3D) shape of the pores in calcareous sand particles,high-precision tomographic images of the calcareous sand particles were obtained using a high-precision X-ray μCT scanning technique. The 3D image of the calcareous sand particles was reconstructed through cutting,denoising,binarization,and other operations on the original CT scan image. As the shape of calcareous sand particles is irregular,it is difficult to extract the internal pores directly. In this paper,a series of algorithms,such as 3D closing algorithm,were used to reconstruct the interior structure of calcareous sand. According to the appearance characteristics of the calcareous sand particles,porosity of the inner pores,shape of the pore size distribution curve,and fractal dimension,calcareous sand particles can be roughly classified into two types. The first type of calcareous sand particles has more gullies on the surface;its inner pores are more developed. The inner pores of the second type of calcareous sand particles are less developed and have lower connectivity. The porosity and pore size distribution curves of the two types of calcareous sand particles are significantly different. Furthermore,it is found that pores in the calcareous sand particles conform to the 3D fractal characteristics, and the value of the fractal dimension is positively correlated with the value of porosity. In order to deeplystudy the connectivity of inner pores in calcareous sand particles,the space network model of the inner pores was obtained by calculating the distance map. It can be concluded that all the distribution of the coordination number of the calcareous sand particle network model has the same general trend. Additionally,owing to the difference in pore morphology between the two types of calcareous sand particl

关 键 词：钙质砂 X射线μCT扫描 内孔隙 孔径分布 分形维数 孔隙网络分析 

分 类 号：TU411[建筑科学—岩土工程]