The increasing understanding of the connection between particle morphology and mechanical behaviour of granular materials has generated significant research on the quantitative characterisation of particle shape. This work proposes a simple and effective method, based on the fractal analysis of their contour, to characterise the morphology of soil particles over the range of experimentally accessible scales. In this paper, three new non-dimensional quantitative morphological descriptors are introduced to describe (1) overall particle shape at the macro-scale, (2) particle regularity at the meso-scale, and (3) particle texture at the micro-scale. The characteristic size separating structural features and textural features emerges directly from the results of the fractal analysis of the contour of the particle, and is a decreasing fraction of particle dimension. To explore the meaning of the descriptors, the method is applied first to a variety of Euclidean smooth and artificially roughened regular shapes and then to four natural and artificial sands with different levels of irregularity. Relationships are established between the new morphological descriptors and other quantities commonly adopted in the technical literature.

中文翻译：

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基于粒子轮廓分形分析的多尺度形态描述子

对颗粒形态与颗粒材料力学行为之间联系的日益了解，已经对颗粒形状的定量表征进行了重要研究。这项工作基于对它们的轮廓进行分形分析，提出了一种简单有效的方法来表征在实验上可达到的范围内的土壤颗粒形态。本文引入了三种新的无量纲定量形态学描述子来描述（1）宏观尺度上的整体颗粒形状，（2）中观尺度下的颗粒规则性和（3）微观尺度下的颗粒纹理。分离结构特征和纹理特征的特征尺寸直接来自粒子轮廓的分形分析结果，并且是粒子尺寸的递减分数。为了探索描述符的含义，该方法首先应用于各种欧氏光滑和人工粗糙化的规则形状，然后应用于四种具有不同不规则度的天然和人工沙子。在新的形态学描述符和技术文献中通常采用的其他数量之间建立了关系。