Error Correction Method for Hydrometer Analysis in Test Method for Particle Size Distribution of Soils

Abstract

In test method for particle size distribution of soils, sieve analysis result and hydrometer analysis result may not be skillfully connected. It is said that in hydrometer analysis, much error arises from many causes, and it'brings about the error for the values of percent finer by mass and particle size calculated using Stokes’ law. This fact was estimated by the trial, and instrumental error of hydrometer, density error of the water, viscosity coefficient error of the water was clarified. Hydrometer analysis result was corrected using these. It was confirmed that the corrected hydrometer analysis result agrees almost with the sieve analysis result using 45 μm sieve, 32 μm sieve and 20 μ msieve. Then, as convenient method, the method for moving particle size curve by hydrometer analysis parallel in the vertical direction was proposed so that the percent finer by mass of 32//m particle size by the hydrometer analysis may agree with the percent finer by mass of 32//m particle size by the sieve analysis, and the result was good.