Development Of Soil Mechanics

Development Of Soil Mechanics

The use of soil for engineering purposes dates back to prehistoric times. Soil was used not only for foundations but also as construction material for embankments. The knowledge was empirical in nature and was based on trial and error, and experience.

The hanging gardens of Babylon were supported by huge retaining walls, the construction of which should have required some knowledge, though empirical, of earth pressures. The large public buildings, harbours, aqueducts, bridges, roads and sanitary works of Romans certainly indicate some knowledge of the engineering behaviour of soil. This has been evident from the Writings  of  Vitruvius,  the  Roman  Engineer  in  the  first  century,  B.C.  Mansar  and Viswakarma, in India, wrote books on 'construction science' during the medieval period.

The Leaning Tower of Pisa, Italy, built between 1174 and 1350 A.D., is a glaring example of a lack of sufficient knowledge of the behaviour of compressible soil, in those days.

Coulomb, a French Engineer, published his wedge theory of earth pressure in 1776,which is the first major contribution to the scientific study of soil behaviour. He was the first to introduce the concept of shearing resistance of the soil as composed of the two

components-cohesion and internal friction. Poncelet, Culmann and Rebhann were the other men who extended the work of Coulomb. D' Arcy and Stokes were notable for their laws for the flow of water through soil and settlement of a solid particle in liquid medium,respectively. These laws are still valid and play an important role in soil mechanics. Rankine gave his theory of earth pressure in 1857; he did not consider cohesion, although he knew of its existence.

Boussinesq, in 1885, gave his theory of stress distribution in an elastic medium under a point load on the surface.Mohr, in 1871, gave a graphical representation of the state of stress at a point, called 'Mohr's Circle of Stress'. This has an extensive application in the strength theories applicable to soil.Atterberg, a Swedish soil scientist, gave in 1911 the concept of 'consistency limits' for a soil. This made possible the understanding of the physical properties of soil. The Swedish method of slices for slope stability analysis was developed by Fellenius in 1926. He was the chairman of the Swedish Geotechnical Commission. Prandtl gave his theory of plastic equilibrium in 1920 which became the basis for the development of various theories of bearing capacity. Terzaghi gave his theory of consolidation in 1923 which became an important development in soil mechanics. He also published, in 1925, the first treatise on Soil Mechanics, a term coined by him. (Erd bau mechanik, in German). Thus, he is regarded as the Father of modern soil mechanics'. Later on, R.R. Proctor and A. Casagrande and a host of others were responsible for the development of the subject as a full-fledged discipline.Fifteen International Conferences have been held till now under the auspices of the international Society of Soil Mechanics and Foundation engineering at Harvard(Massachusetts, U.S.A.) 1936, Rotterdam (The Netherlands) 1948, Zurich (Switzerland) 1953, London (U.K.) 1957, Paris (France) 1961, Montreal (Canada) 1965, Mexico city (Mexico) 1969, Moscow (U.S.S.R) 1973, Tokyo (Japan) 1977, Stockholm (Sweden) 1981, San Francisco (U.S.A.) 1985,and Rio de Janeiro (Brazil) 1989. The thirteenth was held in New Delhi in 1994, the fourteenth in Hamburg, Germany, in 1997 , and the fifteenth in Istanbul, Turkey in 2001. The sixteenth is proposed to be held in Osaka, Japan, in 2005.

These conferences have given a big boost to research in the field of Soil Mechanics and Foundation Engineering