This paper presents a statistical analysis on the relationship between shear strength and water saturation of cohesive soils based on a comprehensive database (labeled as Cohesive Soil/3/2119). In this study, the cohesive soils are categorized into three general types including clay, silty clay, and silt. For each of the three types, the statistical characteristics including mean, standard deviation (SD), coefficient of variation (COV), standard error of mean (SEM), and distribution type of the shear strength parameters at different water saturation intervals are derived. Further, several empirical formulas are proposed for predicting the statistical characteristics of shear strength of cohesive soils as a function of degree of saturation. The empirical formulas and relationships for different soil types are compared. For the three soil types, the decreasing rate of mean cohesion with the increase of water saturation is highest for silt and lowest for clay; however, the decreasing rate for mean friction angle is highest for clay and lowest for silt. The statistics in terms of SD and COV for shear strength versus water saturation are also analyzed. The developed correlations provide useful guidelines in the reliability-based geotechnical design for estimating the statistical characteristics of shear strength of cohesive soils based on the moisture conditions.

本文基于综合数据库（标记为 Cohesive Soil/3/2119）对粘性土的抗剪强度与含水饱和度之间的关系进行了统计分析。在这项研究中，粘性土分为三种一般类型，包括粘土、粉质粘土和粉砂。对于这三种类型中的每一种，推导出了不同含水饱和度区间的抗剪强度参数的均值、标准差（SD）、变异系数（COV）、均值标准误（SEM）和分布类型等统计特征。此外，还提出了几个经验公式，用于预测粘性土的抗剪强度统计特性与饱和度的函数关系。比较了不同土壤类型的经验公式和关系。对于三种土壤类型，随着含水饱和度的增加，平均黏聚力的下降速率以粉砂最高，粘土最低；然而，平均摩擦角的下降率在粘土中最高，而在粉砂中最低。还分析了剪切强度与含水饱和度的 SD 和 COV 统计数据。所开发的相关性为基于可靠性的岩土工程设计提供了有用的指导，用于估计基于水分条件的粘性土壤的剪切强度的统计特征。