ABSTRACT
One of the most fundamental measurements that can be made on the solid phase of soil is used to describe the assemblage of individual grains or particles that make up that soil. This is done by determining the mass of soil grains of different sizes by separating the grains. This procedure is referred to as the grain-size analysis or particle-size analysis and results in a grain-size distribution curve for the soil. The grain-size analysis is performed in two parts: 1) the sieve analysis, and 2) the hydrometer or pipette analysis.
The sieve analysis is used for the coarse fraction and separates particles into different sizes by passing the soil through a series of screens or sieves. The sieves are stacked with the largest size sieve opening at the top and the smallest size sieve opening at the bottom. A pan is placed below the smallest sieve on the bottom to catch any soil that falls through the last sieve. The stack of sieves is usually called a “nest” of sieves. Dry soil is poured into the top sieve, the lid is placed on top and the sieves are placed on a mechanical shaker so that particles fall by gravity until they are held on a screen with an opening smaller than the equivalent diameter of the soil particle. After shaking, the sieves are taken apart and weighed so that the mass of soil held or retained on that sieve is determined. The sieve analysis works best for coarse-grained soils, such as gravels and sand, that have particles that are large enough to be seen by the naked eye and are easily separated.
