Knowledge of the use of soil extends into prehistoric times, when man started constructing dwellings for living and roads for transportation. In the more primitive civilizations, soil was used by man as a construction material for foundations of structures and for the structures themselves. The knowledge of soils for the foundations, bunds and roads was gained by trial and error experiences. Through ancient times and even within the last few generations, practically all improvement was the result of a continuous broadening by empirical knowledge. 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 BC 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 eighteenth 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.
Many structures were built in the medieval period (about AD 400–1400). One of the main problems they had was about the compression of soil and the consequent settlement of buildings. During the past centuries, the compressible soil upon which heavy structures such as cathedrals were built had enough time to consolidate, causing large settlements. The Leaning Tower of Pisa is an example. In India, the Taj Mahal was constructed between 1632 and 1650. It had unique foundation problems because of its proximity to the river Jamuna. Several foundation-related engineering problems, such as for the Leaning Tower of Pisa, prompted scientists to begin taking a more scientific-based approach to examining the subsurface.
Classical geotechnical mechanics began in 1773 with Charles Coulomb’s 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 failure criteria for soil. By combining Coulomb’s theory with Christian Otto Mohr’s theory of a 2-D stress state, the Mohr–Coulomb theory was developed – a very useful graphical construction still used today. A rudimentary soil classification system was also developed based on a material’s unit weight, which is no longer considered a good indication of soil type.
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