Test method for determination of optimum moisture content of soil and maximum dry density

Abstract

A method for accurately determining the optimum water content of soil and the corresponding maximum dry density has been developed using a small number of soil samples, based on the physical parameters of the confined compression modulus of soil. The peak value of the compression modulus on the force-compression modulus curve is used to determine the optimum moisture content and maximum dry density. The proposed method is validated using four different types of soils: Qinghai-Tibet clay, SiO2-clay, Lanzhou loess, and Qinghai-Tibet sand soil. The results show that as opposed to conventional compaction methods, the new method allows for accurate determination of the optimum water content and the maximum dry density for various types of soil. Additionally, for certain moisture contents, when the compaction of soil is the greatest, clay and SiO2-clay attain the theoretical saturation status, whereas sand soil and loess do not.