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WEL-COME

The Maharaja SayajiRao University of Baroda

Polytechnic

Prepared by: Nilesh KachotMSU Polytechnic_TYD_Civil_Div:1_Rollno.:37

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A Brief Presentation on……

“HISTORY OF

SOIL MECHANICS”

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* TOPICS

What is “soil”? Soil mechanics. History of soil engineering. Field of soil mechanics.

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WHAT IS “SOIL”?

Soil is the mixture of minerals, organic matter, gases, liquids, and the countless organisms that together support life on Earth.

Soil is considered to be the "skin of the Earth. It includes widely different materials like

sand, gravels, clays and silts. The type of soil depend upon the size of

particles i.e. sandy soil, loamy soil, etc and on the color of soil i.e. yellow soil, black soil, etc.

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SOIL MECHANICS…

Soil Engineering, Soil Mechanics or Geotechnique is one of the youngest disciplines of civil engg. involving the study of soil, its behavior and applications as an engineering material.

Soil mechanics is a branch of engineering mechanics that describes the behavior of soils.

Soil mechanics is used to analyze the deformations of and flow of fluids within natural and man-made structures that are supported on or made of soil, or structures that are buried in soils.

It is useful for building and bridge foundations, retaining walls, dams, and buried pipeline systems, etc.

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HISTORY OF SOIL ENGINEERING.

Beginning of use of soil in pre-historic time..- For Habitation, roads, etc.- As a construction material.- Fundaments of foundations & roads from the trial and error experience.- Use of ‘timber + stone caissons’ of soft ground shaft construction was known in Egypt in 2000 B.C.-

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HISTORY OF SOIL ENGINEERING.

Began: 18th century since then, the science of Soil mechanics has evolved through 4 phases…

Pre-classical (1700 A.D. to 1776 A.D.) Classical phase-1 (1776 A.D. to 1856 A.D.) Classical phase-2 (1856 A.D. to 1910 A.D.) Modern (1910 A.D. to present)

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SOIL ENGINEERING PRIOR TO THE 18TH CENTURY The record of the first use of soil as a

construction material by mankind is lost in antiquity. In true engineering sense, there is no ‘Soil Engineering’ prior to the 18th Century.

For years, the art of Soil engineering and Geotechnical engineering was based on only past experiences through a succession of experimentation without any real scientific character.

Based on those experimentations, many structures were built—some of which have crumbled, while others are still standing.

Continue….

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One of the greatest structures in ancient times was the famous ‘Hanging Garden’ built by the Babylonian King Nebuchdnezza.

Continue….

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One of the most famous examples of problems related to soil bearing capacity and foundations in the construction of structures prior to 18th century is the Leaning Tower of Pisa in Italy. The construction of the Tower began in 1173 and last over 200 years.

The tower has tilted in the past to the east, north, west and, finally, to the south.

Recent investigations showed that a weak clay layer exists at a depth of about 11 m below the ground surface compression, which caused the tower to tilt.

Continue….

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PRE-CLASSICAL PERIOD OF SOIL MECHANICS This period concentrated on studies relating

to natural slope and unit weights of various types of soils, as well as the semi empirical earth pressure theories.

Henri Gautier (1660–1737) studied the natural slopes of soils when tipped in a heap for formulating the design procedures of retaining walls.

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Bernard Forest de Belidor (1671–1761 French engg.) proposed a theory for lateral earth pressure on retaining walls specified a soil classification system.

Francois Gadroy (1705–1759) observed the existence of slip planes in the soil at failure.

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CLASSICAL SOIL MECHANICS Classical Soil Mechanics

began in 1773 with Charles Coulomb’s (a physicist, 1736–1806) 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 2D stress state, the Mohr Coulomb theory was developed.

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Henry Darcy (1803–1858) defined the hydraulic conductivity.

Joseph Boussinesq, a mathematician and physicist (1842–1929), developed the theory of stress distribution.

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William Rankines (1820–1872) simplified Coulomb's earth pressure theory.

o Osborne Reynolds (1842–1912) demonstrated the phenomenon of dilatency in sand

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MODERN SOIL MECHANICS

This period was marked by a series of important studies and publications related to the mechanic behavior of clays.

Albert Atterberg (1846–1916), a Swedish chemist and soil scientist, explained the consistency of cohesive soils by defining liquid, plastic, and shrinkage limits.

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Arthur Bell (1874–1956), a civil engineer from England, developed relationships for lateral pressure and resistance in clay as well as bearing capacity of shallow foundations in clay.

Wolmar Fellenius (1876–1957), an engineer from Sweden, developed the stability analysis of saturated clay slopes.

Karl Terzaghi (1883–1963), a civil engineer and geologist from Austria, developed the theory of consolidation for clays as we know today..

Wolmar Fellenius

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The development of modern Geotechnical Engineering as a branch of Civil Engineering is absolutely impacted by one single professional individual – Karl Terzaghi.

Generally recognized as the father of modern soil mechanics and geotechnical engineering.

He started modern soil mechanics with his theories of consolidation, lateral earth pressures, bearing capacity, and stability.

His contribution has spread to almost every topic in soil mechanics and geotechnical engineering covered by the text book: Effective stress; Elastic stress distribution; Consolidation settlement; Shear strength; in situ testing

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ACCORDING TO TERZAGHI (1948) “Soil mechanics is the

application of laws of mechanics and hydraulics to engineering problems dealing with sediments and other unconsolidated accumulations of solid particles by mechanical and chemical disintegration of rocks regardless of whether or not they contain an admixtures of organic constituents.”

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FIELD OF SOIL MECHANICS Soil mechanics field is very fast. Following are some important problems in

civil engineering…

Foundation design and construction. Design of Pavement. Design of underground and earth retaining

structures. Design of embankment and cutting. Design of Earthen Dam.

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Thank You….

Prepared by: Nilesh KachotMSU Polytechnic_TYD_Civil_Div:1_Rollno.:37