Geotechnical engineering

Geotechnical engineering is the field of engineering concerned with earth materials, such as soils and rocks.

## Soil mechanics[edit]

Soil mechanics is a key area of geotechnical engineering. Soils are made up of solid rock or mineral particles, water, and air. These three are known as the phases of soil. There are a number of standard properties of soil which are used in geotechnical engineering:

* Unit weight: the weight of a unit volume of soil.
* Voids ratio: the ratio of the volume of voids (Vv) to the volume of solids (Vs).
* Porosity: the ratio of the volume of voids (Vv) to the volume of the soil.
* Shear strength: the shear stress which causes the soil to fail.