土的压实特性是水利工程中非常令人关注的特性之一。为研究细粒土压实特性与颗粒组成的相关性,结合2017年以来实施的8个水利工程勘察项目,在试验要求统一的前提下,收集了123组击实试验、颗粒分析试验数据,试验样品主要集中在安徽省内长江与淮河之间的200余公里范围内。对细粒土的最大干密度、最优含水率与黏粒、粉粒和砂粒数据之间的相关性开展了一元和二元线性回归分析。在剔除了黏粒含量>37%的7组数据后,得到了以黏粒、粉粒含量为自变量,以最大干密度、最优含水率为因变量的二元线性回归分析结果。研究结果表明:影响细粒土压实特性的主要因素是颗粒组成,但土中的水和气等因素也对压实特性产生一定影响;当细粒土黏粒含量在10%~37%时,最大干密度、最优含水率与颗粒组成有较好的相关性; 目前工程中常用的击实试验和颗粒分析试验方法存在精度较差、人为因素影响大等缺陷。研究成果可为进一步明确细粒土压实特性提供参考。

The compactability of soil plays a very important role in water conservancy project. In order to study the correlation between fine-grained soil’s compactability and particle composition , according to eight water conservancy projects since 2017, we collected data of compaction test and grain size test. Most test samples are collected from a range of about 200 km between Yangtze river and Huaihe river in Anhui province. The correlation between maximum dry density, optimum water content of fine-grained soil and sand-silt-clay data was examined by simple linear regression and binary linear regression. A binary linear regression result was obtained by using clay-silt content as independent variable and maximum dry density and optimum water content as dependent variable while excluding the data of clay content larger than 37%. Results suggest that particle composition is the major factor affecting the compactability of fine-grained soil, while water and gas in soil also have some effects on the compactability at the same time. A good correlation was found between maximum dry density and optimum water content and soil composition while fine-grained soil content is in the range from 10% to 37%. This study will help us to understand the compactability of fine-grained soil meanwhile avoid poor accuracy and artificial factor during compaction test and grain size test.