ABSTRACT
Soil properties depend on (1) the state of the soil – its air-water-solid phase mix and (2) the type of soil – its classification, grain size, and plasticity. Soil composition, description, classification, and key phase relationships definitions are covered in this chapter. This understanding is a necessary first step in all earthwork projects. Testing standards must be understood as sample preparation can affect test results. The classification leads to an engineering use; this classification acts as a guide as to the likely design or construction issues one may encounter. Residual soils do not fall neatly into this much-used classification system. A case study is used to show how one of the simplest tests (a grading) may not be representative of in-situ conditions and requires interpretation to be correctly applied.
