概述了液塑限联合测定法的基本原理、试验方法和步骤.对界限含水量的确定方法,特别是对作图法和解析法进行了探讨.在此基础上,以湘潭市某城市主干道路基粉质粘土为研究对象,采用液塑限联合测定法进行了不同含水量下的锥入深度测定.运用作图法和解析法,得出了不同土样的液限和塑限值.采用2种方法所获结果的对比分析表明:解析法不仅方法简便、结果准确,而且效率很高,是一种值得推广的方法. The basic principles, test methods and steps of the combined determination of liquid and plastic limit are summarized.The method of determining the limit water content, especially the mapping and analytic methods are discussed.On this basis, the main trunk of a city in Xiangtan Subgrade silty clay was taken as the research object, the depth of conic penetration under different water content was determined by the liquid-plastic combined test method.The liquid and plastic limit values ​​of different soil samples were obtained by the method of plotting and analytic.Using Comparative analysis of the results obtained by the two methods shows that the analytical method is not only simple, accurate, but also highly efficient, which is worthy of promotion.