ABSTRACT
Classification of soils should be based on the needs of the user. This chapter presents several of the most common systems of soil classification. While each system was developed for a specific purpose, some data included in each can be transferred to other uses. The most fundamental classification system utilizes particle size distribution. Particle size distribution provides an indication of the gross surface area of mineral particles which may be available for reaction. The slope of the particle size distribution curve indicates the possible packing density of the soil that is directly related to permeability. The particle size distribution of clay and silt materials is determined by observing the settling time of the particles in water as described by Stoke’s law. The physical properties of most fine grained soils are controlled by water content. The shape of individual particles has important influence on the physical properties of soil.
