土颗粒的大小及其组成,与其物理力学性质有密切的关系。根据颗粒组成进行分类,就可以概略地判定土的透水性,可塑性,收缩、膨胀等物理力学性质,以作为工程地质评价的依据。土的颗粒分析试验,一般采用比重计法,此方法在土工试验中较为烦琐,为此不少单位作了改进。水利电力部《土工试验操作 The size and composition of soil particles are closely related to their physical and mechanical properties. According to the classification of particle composition, it is possible to roughly determine the physical and mechanical properties of soil such as water permeability, plasticity, shrinkage, and expansion, and use it as the basis for engineering geology evaluation. The soil particle analysis test generally uses the pycnometer method. This method is more tedious in the geotechnical test. Therefore, many units have made improvements. Ministry of Water Resources and Electricity