The organization and presentation of the soils report is highly important. The report must be well-organized and must be presented in a logical and concise format with emphasis on technical conclusions. The principal objective of soil classification is the prediction of engineering properties and behavior of a soil based on a few simple laboratory or field tests. The results of these tests are then used to identify the soil and put it into a group of soils that have similar engineering characteristics. Soils seldom exist in nature separately as sand, gravel, or any other single component.
Soils usually form mixtures with varying proportions of different size particles.
Each component contributes to the characteristics of the mixture. The USCS is based on the textural or plasticity-compressibility characteristics that indicate how a soil will behave as a construction material. If 50 percent or more of the soil by weight is retained on a No. 200 sieve, then the soil is coarse-grained. It is fine-grained if more than 50 percent passes the No. 200 sieve. Highly organic soils can generally be identified by visual examination.