液限和塑限分别是细粒土呈可塑状态的上限含水量和下限含水量。它是粘性土的两个重要物理指标。用它可以计算塑性指数、液性指数(结合土的含水量),以及对(细粒)土进行工程分类等。因此,准确测定粘性土的液限、塑限就具有重要的意义。液限、塑限联合试验是采用光电式液、塑限联合测定仪,用76g 圆锥仪测定在5s 时土在不同含水量时的圆锥下沉深度。在双对数坐标纸上绘成圆锥下沉深度和含水量的关系直线, The liquid limit and the plastic limit are respectively the upper limit water content and the lower limit water content of the fine grained soil in a plastic state. It is two important physical indicators of clay. It can be used to calculate the plasticity index, liquid index (combined with the soil moisture content), as well as the (fine-grained) soil engineering classification. Therefore, the accurate determination of the liquid limit of clay, plastic limit is of great significance. Liquid limit, plastic limit joint test is the use of optical liquid, plastic limited joint detector, with 76g cone instrument in 5s when the soil depth of cone sinking at different water content. Draw the relationship between cone sinking depth and water content on double logarithmic coordinate paper Straight line,