ABSTRACT
Geotechnical design is as much art as science. It is the geotechnical engineer's responsibility to determine how much to trust those data, how to interpret them, and ultimately to communicate how the soil at a particular site will behave. Soil is a natural aggregate of mineral grains, with or without organic components that can be separated by mechanical means. Rock is an aggregate of mineral grains bound by much stronger cohesive forces. The most common classification used for vertical construction is the Unified Soil Classification System (USCS), as adopted by the American Society for Testing and Materials International. The USCS uses index properties to define soil types; these are grain size, grain size distribution, liquid limit, and plasticity index. One of the most important things to know about in situ soil is water content, which is the ratio of the weight of water to the weight of dry soil solids in a sample.
