基于CT扫描及图像处理技术的机制砂形貌研究

Study on Morphology of Manufactured Sand Based on CT Scanning and Image Processing Technology

目前关于机制砂形貌的研究往往集中在以球形度为代表的宏观参数上,这可能存在一定的片面性。为从宏观到微观系统地研究机制砂形貌,本工作将砂形貌参数分为四个维度,即球形度、凸率、粗糙度、比表面积;基于CT扫描采集了三种岩性、两个粒级的砂样数字图像,使用Avizo、Matlab软件经图像处理后定量计算出砂粒形貌参数;建立了形貌参数函数公式,揭示了四个维度参数之间的相互关系。研究表明:该图像处理方法可以较高精度地计算出砂形貌参数;将砂粒表面通过SEM分别放大50倍、200倍后,可以进一步发现凸率适合于描述放大50倍的砂形貌,表面粗糙度适合于描述放大200倍的砂形貌;球形度、凸率、粗糙度与粒级无关,比表面积与粒级成反比;球形度与凸率服从Weibull分布,而粗糙度与比表面积服从正态分布。

At present,the research on the morphology of manufactured sand often focuses on the macro parameters represented by sphericity,which may be a certain one-sided in this.To comprehensively study the morphology of manufactured sand from macro to micro,the sand morpho-logy parameters are decomposed into the following four dimensions:sphericity,convex ratios,roughness and specific surface area.Based on CT scanning,digital images of sand samples of 2 particle sizes and 3 lithologies were collected,and the sand morphology parameters were calcula-ted quantitatively after the image was processed by Avizo and Matlab software;the function formula of morphology parameters was established,and the relationship between the four dimensional parameters was revealed.It is found that:the image processing method can calculate the sand morphology parameters with high accuracy;after magnifying the sand surface 50 and 200 times by SEM,it can be further found that the convex ratios is suitable for describing the sand morphology at a magnification of 50 times,and the surface roughness is suitable for describing the sand morphology at a magnification of 200 times;sphericity,convex ratios,and roughness are independent of particle size,the specific surface area is inversely proportional to particle size;it is concluded that sphericity and convex ratios obey Weibull distribution,while roughness and specific surface area obey normal distribution.