Geotechnical

A geotechnical engineer then determines and designs the type of foundations, earthworks, and/or pavement subgrades required for the intended man-made structures to be built. Foundations are designed and constructed for structures of various sizes such as high-rise buildings, bridges, medium to large commercial building, and smaller structures where the soil conditions do not allow code-based design.

Geotechnical engineering is also related to coastal and ocean engineering. Coastal engineering can involve the design and construction of wharves, marinas, and jetties. Ocean engineering can involve foundation and anchor systems for offshore structures such as oil platforms.

Humans have historically used soil as a material for flood control, irrigation purposes, burial sites, building foundations, and as construction material for buildings. First activities were linked to irrigation and flood control, as demonstrated by traces of dykes, dams, and canals dating back to at least 2000 BCE that were found in ancient Egypt, ancient Mesopotamia and the Fertile Crescent, as well as around the early settlements of Mohenjo Daro and Harappa in the Indus valley. As the cities expanded, structures were erected supported by formalized foundations; Ancient Greeks notably constructed pad footings and strip-and-raft foundations. Until the 18th century, however, no theoretical basis for soil design had been developed and the discipline was more of an art than a science, relying on past experience.

Classical geotechnical mechanics began in 1773 with Charles Coulomb's (a physics) introduction of mechanics to soil problems. Using the laws of friction and cohesion to determine the true sliding surface behind a retaining wall, Coulomb inadvertently defined a failure criteria for soil. By combining Coulomb's theory with Christian Otto Mohr's theory of a 2D stress state, the Mohr-Coulomb theory was developed, a graphical construction still used today.

Modern geotechnical engineering began in 1925 with the publication of Erdbaumechanik by Karl Terzaghi (a civil engineer and geologist). Generally recognized as the father of modern soil mechanics and geotechnical engineering, Terzaghi's research on the settlement of clays and failure due to piping beneath dams was considered groundbreaking.

Geotechnical engineers are typically graduates of a four-year civil engineering program and often hold a masters degree. In the USA, geotechnical engineers are typically licensed and regulated as Professional Engineers (PEs) in most states; currently only California and Oregon have licensed geotechnical engineering specialties. State governments will typically license engineers who have graduated from an ABET accredited school, completed several years of work experience, and passed the professional engineering examination.

In geotechnical engineering, soils are considered a three-phase material composed of: rock or mineral particles, water and air. The voids of a soil, the spaces in between mineral particles, contain the water and air.

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