Soil Mechanics

soil, mechanics

Soil mechanics is the branch of engineering science which deals with the behavior of soil when it is subjected to stresses or to the action of percolating water. This subject gives a rational basis for foundation engineering and earth-dam design and provides new tools for geological investigation. The accuracy with which settlings can be predicted on the basis of soil mechanics varies with the geology and character of the given deposits. Under the best conditions, computed and observed settlings agree satisfactorily until the settling reaches about 60% of the computed final value. The real settlings exceed the computed ones only by an amount that is usually a small fraction of the total settling. Soil is a natural aggregate of mineral grains, with or without organic constituents. These grains can be separated by a mechanical means such as agitation in water. Soil may consist of the products of rock decomposition or of materials transported and deposited by streams or wind. Soil differs from most structural materials in that it consists of three phases: solid mineral matter, water, and air or other gas. Many soils consist of two-phase systems of mineral matter and water, and then they are called saturated.