【摘要】 为定量研究不同粒级石灰石机制砂形貌特征及规律,使用数码相机和体式显微镜采集了4.750~2.360、2.360~1.180、1.180~0.600、0.600~0.300、0.300~0.150 mm和0.150~0.075 mm共6个粒级石灰石机制砂的数字图像(每一粒级以500粒为样本容量);基于数字图像处理(digital image processing,DIP)技术,使用软件Image-Pro Plus定量测定了样本的圆度、轴向系数和球度,通过分形理论计算了石灰石机制砂的分形维数;对不同形貌特征进行统计分析,并和天然河砂的形貌参数作了对比.研究结果表明:不同粒级石灰石机制砂的圆度、轴向系数和球度分布基本符合正态分布;不同粒级机制砂或河砂的圆度、轴向系数、球度和分形维数变化具有良好的一致性,砂粒形貌特征可采用任意一种参数表征;石灰石机制砂的圆度、轴向系数和球度分别为0.834~0.857、0.693~0.705和0.793~0.799,分别低于河砂5.0%、7.2%和3.3%,分形维数为1.046~1.056,高于河砂3.2%;提出了机制砂整形过程中圆度、轴向系数、球度和分形维数的建议取值范围,分别为0.880~1.000、0.740~1.000、0.820~1.000和1.010~1.025.更多还原

【Abstract】 To quantitatively study the morphological characteristics and regularity of limestone manufactured sand with different particle sizes,digital images of 6 size fractions in total,4.750-2.360,2.360-1.180,1.180-0.600,0.600-0.300,0.300-0.150 mm and 0.150-0.075 mm(sample size of each size fraction is 500),were collected by digital camera and stereomicroscope.Based on digital image processing(DIP), the circularity,aspect ratio and sphericity of samples were quantitatively determined using software Image-Pro Plus.While the fractal dimension of limestone manufactured sand was calculated according to fractal theory.Besides,statistical analysis was used for the morphology characteristics,and the morphology parameters of limestone manufactured sand and river sand were compared.The results indicate that the circularity,aspect ratio and sphericity of limestone manufactured sand with different sizes basically obey the normal distribution.For differentsize fractions,the changes of circularity,aspect ratio,sphericity and fractal dimension are consistent,signifying that the morphology parameters of limestone manufactured sand or river sand can be characterized by either one of these parameters.The circularity,aspect ratio and sphericity of limestone manufactured sand are 0.834-0.857,0.693-0.705 and 0.793-0.799,less than those of river sand by5.0%,7.2% and 3.3%,respectively,while its fractal dimension reaches 1.046-1.056,higher than that of the river sand by 3.2%.Finally,the recommended ranges of roundness,aspect ratio,sphericity and fractal dimension in the process of manufactured sand shaping were provided,i.e.,0.880-1.000,0.740-1.000,0.820-1.000 and 1.010-1.025.更多还原