GEOTECH Flashcards
Soil
is defined as the uncemented aggregate of mineral grains and
decayed organic matter (solid particles) with liquid and gas in the empty spaces between the solid particles.
Soil Mechanics
is the branch of science that deals with the study
of the physical properties of soil and the behavior of soil masses
subjected to various types of forces.
Soil Engineering
is the application of the principles of soil
mechanics to practical problems.
Geotechnical Engineering
is the sub discipline of civil engineering that involves natural materials found close to the surface of the earth. It includes the application of soil mechanics and rock
mechanics to the design of foundations, retaining structures and
earth structures.
18th century
___________ when the understanding of
geotechnical engineering as it is known today began
in true engineering terms (Skempton, 1985).
▪ Ancient civilizations flourished along the banks of
rivers (Nile in Egypt, Tigris and Euphrates in
Mesopotamia, Huang Ho or Yellow river in China and
Indus in India).
▪ There is no evidence that measures were
taken to stabilize the foundations or check
erosion caused by flood (Kensel, 1986).
Leaning Tower of Pisa (Italy)
most famous example of problems related to soil bearing
capacity in the construction of structures.
Construction began in 1173 AD and continued
for over 200 years.
Four major periods in geotechnical engineering based on emphasis
and nature of study
- Pre classical (1700 to 1776 AD)
- Classical Soil Mechanics – Phase 1 (1776 to 1856 AD)
- Classical Soil Mechanics- Phase 2 (1856 to 1910 AD)
- Modern Soil Mechanics (1910 to 1927 AD)
Pre-Classical Soil Mechanics (1700 – 1776)
This period concentrated on studies relating to
natural slope and unit weight of various types of
soils, as well as the semi empirical earth pressure
theories.
Pre-Classical Soil Mechanics (1700 – 1776)
Henri Gaulter (1660-1737)
french royal
engineer, in 1717 studied the natural slopes of
soils when tipped in a heap for formulating the
design procedures of retaining walls.
Pre-Classical Soil Mechanics (1700 – 1776)
Bernard Forest de Belidor (1671-1761)
published a text book in 1729 in France. He proposed a theory for lateral earth pressure on
retaining walls that was a follow up to Gautier’s
(1717) original study.
Pre-Classical Soil Mechanics (1700 – 1776)
Francois Gadroy (1705-1759)
- French engineer, in 1746 the
first laboratory model test results on retaining wall w/ sand
backfill was reported. - Observe existence of slip planes in the soil at failure
Pre-Classical Soil Mechanics (1700 – 1776)
J.J. Mayniel (1808)
Summarizes Gadroy’s study.
Classical Soil Mechanics – Phase 1 (1776-1856)
Charles Augustin Coulomb (1736-1806)
in 1776,
used calculus to determine the true position of the
sliding surface in soil behind a retaining wall. He
used laws of friction and cohesion for solid bodies.
Classical Soil Mechanics – Phase 1 (1776-1856)
▪ Jacques Frederic Francais (1775-1833) and Claude
Louis Marie Henri Navier (1785-1836)
In 1820,
French engineer and french applied mechanics
professor respectively, studied special cases of
Coulomb’s work w/c are related to inclined
Retaining Wall Collapse backfills and backfills supporting surcharge.
Classical Soil Mechanics – Phase 1 (1776-1856)
Jean Victor Poncelet (1788-1867)
army engineer and professor of mechanics, in 1840
extended Coulomb’s theory by providing a
graphical method for determining the
magnitude of lateral earth pressure on vertical
and inclined retaining walls with arbitrarily
broken polygonal ground surfaces, first to use
the symbol φ for soil friction angle, provided the
first ultimate bearing-capacity theory for
shallow foundations.
Classical Soil Mechanics – Phase 1 (1776-1856)
Alexandre Collin (1808-1890)
In 1846, an
engineer, provided the details for deep slips in
clay slopes, cutting and embankments.
Classical Soil Mechanics – Phase 1 (1776-1856)
William John Macquorn Rankine (1820-1872)
In 1857, professor of civil engineering at the
University of Glasgow published a study in w/c
provided a notable theory on earth pressure and
equilibrium of earth masses. Rankine’s theory is
a simplification of Coulomb’s theory.
Classical Soil Mechanics – Phase 2 (1856-1910)
Henri Philibert Gaspard Darcy (1803-1858)
French
engineer, in 1856 published a study on permeability of
sand filters.