中文摘要：

土体的结构特性研究是土力学和土质学研究的前沿课题，而关于土颗粒定向特性的定量研究方法相对较少，某些方法由于需要过多的人为判断而缺乏客观性。引入ArcGIS中用于点集分布特征的分析方法——标准差椭圆法，通过微观结构图像的转换和处理，利用标准差椭圆给出图像中所有颗粒的定向角分布，进而计算土样的主定向角和各向异性率。该方法为颗粒定向的定量研究提供了一个科学、客观和可靠的手段。

英文摘要：

Studies on soil microstructure are the front edge quantitative studies on the orientation characteristics of soil of the subject on soil mechanics and soil properties. However, the grains in the soil microstructural images （SEM） are an intractable subject in the past decades. An analytical method called the standard deviational ellipse method, which is often used for point set distribution analysis in geographical information system （GIS）, is introduced for quantitative analysis of soil grains. Through the conversion and processing of soil microstructural images, the orientation angles of soil grains＇ can be fast determined by using the standard deviational ellipse method, and the correlative data can be statistically analyzed, and then the characteristic of the soil grain orientation distribution can be obtained. The results show that the method is more scientific, objective and reliable for the quantitative studies on soil grain orientation distribution.