碎石颗粒形状测量与评定的初步研究

颗粒形状是影响碎石料密实特性及力学、渗流特性的因素之一。选取粒径为2～5 mm和5～10 mm的两组灰岩碎石颗粒样本作为研究对象，采用影像测量仪和特制夹具，获取不同旋转角度下的颗粒轮廓影像；使用图形处理软件获得颗粒几何尺寸测值；计算获得各旋转角度下常用颗粒形状评定参数值，运用其平均值进行统计分析，避免了依据单一角度测值评定伴随的人为因素影响。结果表明，灰岩碎石颗粒与标准圆有较大差异, 且粒径大者差异性更明显；两组样本颗粒形状参数均服从偏态分布；长宽比、扁平度和球形度能够更敏感地反映颗粒偏离球形颗粒的程度，而长宽比和球形度便于获取，因而更具优势。

A preliminary study of measurement and evaluation of breakstone grain shape

The shape of grains is one of the main factors influencing the compaction, mechanical and hydraulic properties of breakstone material. Two sets of limestone gravel with diameters of 2-5 mm and 5-10 mm were examined using the image measuring instrument and special fixture, from which the grain appearance images were obtained at different rotation angles. The geometric sizes of grains were measured with graphic software. The common grain shape parameters were calculated from each image at different rotation angles. The mean values of each parameter at different rotation angles for each grain were analyzed, so that the influences of human factors on measured value at just one section were avoided on grain shape evaluation. All the grain shape parameters of limestone gravel show significant differences compared to spherical grains, and the differences of the set with larger size are more obvious. The grain shape parameters of the two set samples can be characterized by skew distribution. The parameters of length-width ratio, flatness and sphericity can more sensitively reveal the differences. Compared to other parameters, it is more straightforward to determine the length-width ratio and sphericity.