土的可塑性是粘性土区别于砂性土的重要特征。可塑性的大小是以土处在塑性状态的含水量变化范围（从组限到液限）来衡量。塑性指数是土的液、塑限之差值（不带“％”号），它在一定程度上综合反映1影响粘性特性的各种重要因素，因此，工程上普遍按塑性指数对粘性上进行分类。土 Plasticity of soil is an important feature of clay soil distinguishing it from sandy soil. The size of plasticity is measured by the change in the moisture content of the soil in the plastic state (from the group limit to the liquid limit). The plasticity index is the difference between the liquid and plastic limits of the soil (without the “%” symbol). It comprehensively reflects, to a certain extent, various important factors affecting the viscous properties. Therefore, the plasticity index is generally applied to the viscosity in engineering. classification. earth