砂卵石粗粒土颗粒外形特征测量与评定初探

A preliminary study of measurement and evaluation of geometry characteristics of coarse gravel

粗粒土颗粒的外形特征是影响其力学特性及渗流特性的重要因素之一。采用室内试验分析的手段对颗粒的外形特征进行了研究。选取粒径分别为10～20、20～40、40～60 mm的两种不同形状的砂卵石粗粒土颗粒,在风干状态下通过排水法分别测定其体积,通过蜡膜厚度估算法测定其表面积,对颗粒体积及表面积关系进行数学拟合,建立了一定粒径范围内两种不同外形砂卵石粗粒土颗粒体积与表面积之间的函数关系。通过类比,发现试验所得出的两个拟合函数关系式和同体积标准球体的体积与表面积关系式具有十分相似的形式,据此提出了类圆度的概念及类圆度系数的计算方法,为颗粒外形特征的定量描述提供了一种方法与思路。

The geometry is one of the key factors which can influence the mechanical and hydrological properties of coarse granular soil In this article, the laboratory test and analysis method are adopted to study the particle appearance characteristic. Two types of coarse granular soil particles with different appearance characteristics are selected in the particle diameters of 10--20 mm, 20--40 ram, 40--60 mm separately. The wax-coated method is used to measure the volume, and the particle surface area is calculated by measuring the thickness of the wax coating. By building the mathematical fitting between the particle volume and the surface area, the correlations between volume and surface area of the two coarse granular soil particles are founded. With analogy, the two fitting equations proposed in this paper are found to be in excellent agreement with that of normative sphere, thus the concept of sphericity-similarity is raised and the coefficient of sphericity-similarity is calculated, which providing a method to describe the appearance characteristic of particle quantitatively.