论述了砂土剪胀性特点和状态参数概念.通过对现有试验结果的对比分析,建立了相变线的概念,提出了相变孔隙比和相变应力比的定义和计算公式.提出了状态参量的计算公式和依据状态参量判别砂土剪胀(缩)的具体方法,并建立了砂土的剪胀比计算公式.为建立砂土本构模型提供依据. The characteristics of dilatancy of sand and the concept of state parameters are discussed.The concept of phase transition line is established by comparing and analyzing the existing test results and the definition and calculation formula of phase change void ratio and phase transformation stress ratio The calculation formula of state parameters and the specific method of judging the dilatancy (shrinkage) of sand based on the state parameters, and the formula of calculating the dilatancy ratio of sand is established, which provides the basis for the constitutive model of sand.