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GEOTECHNICAL ENGINEERI

CHAPTER 1

INTRODUCTION TO GEOTECHNICAENGINEERING

References:

An Introduction to Geotechnical Engineering by: Robert Holtz, WilliamD. Kovacs, and Thomas C. Sheanan

Introduction to Geotechnical Engineering by: Braja M. Das

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DEFINITIONS

Soil unconsolidated or uncemented aggregate of mineral grains decayed organic matter with liquid and gas in the empty spaces bethe solid particles.

Geotechnical Engineering- subdiscipline of civil eng

that involves natural materials found close to the su

the earth (soil and rock). It includes the applicationprinciples of soil mechanics and rock mechanics to

design of foundations, retaining structures, and eart

structures.

Soil Mechanics- deals with the study of physical pro

soil and the behavior of soil masses subjected to vatypes of forces.

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DEFINITIONS

Foundation Engineering applies engineering geosoil mechanics, rock mechanics and structural

engineering to the design and construction offoundations for civil engineering and other structur

Rock Engineering- analogous to foundationengineering for soils, is concerned with rock a

foundation and construction material. Geoenvironmental

Engineering- interdisciplin

field that is involved in the solution of

environmental problems involving soil and ro

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UNIQUE NATURE OF SOIL MATERIAL

Gravel Sand

Silt Clay

--cohesionless--

--cohesive--

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Soils are particles of rock- broken up pieces of rock.

Unique nature of soil materials

Soils are heterogeneous rather than homogeneous

Soils are nonlinear-their stress-strain curves are not s

lines.

Soils are non-conservative-they have fantastic memremember almost everything that ever happened t

this fact strongly affects their engineering behavior.

Lets complicate things!!!

Soils are anisotropic-their material or engineering pr

are not the same in all directions

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A successful geotechnical engineer must develop a feeand rock behavior before a safe and economic foundati

design can be made, an earth structure can be safely buenvironmentally sound waste containment and disposala site remediation plan can be developed.

Remember

Soils and Rocks are indeed complex engineering

construction materials.

To summarize..

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Historical Background

Leaning Tower of Pisa

Built prior to 18th century

Supported by a circularof 20m

Tilted by more than 5m

plumb to south with the

height

Weak clay layers exists adepth of about 11 m be

ground surface

Stabilized by excavation

leans 5 degrees.

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Historical Background

Garisenda Tower (left) and Asinelli Tower (rig

Built 12th century in Italy

Garisenda tower tilted degrees

Asinelli tower tilted 1.3degrees.

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Geotechnical Engineering after 192

Karl Terzaghi1883-1963

C.A.Coulomb

1736-1806

WJM Rankine

1820-1872

A.Casagrande1902-1981 A.W.Skempton1914

R. P

Fatherof modern

SoilMechanics

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Geotechnical Engineering Landmar

Hoover Dam (USA)

Tallest (22

concrete

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Geotechnical Engineering Landmar

Burj Khalifa (Dubai)

Tallest (829.8

Man made stru

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Geotechnical Engineering LandmarMonuments

13

and.

Suggestions to the Study of

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Attend the lectures- it takes longer to understand from the lecture notes

Suggestions to the Study ofGeotechnical Engineering

Knowledge of geology Knowledge of engineering mechanics, streng

of materials and fluid mechanics

Develop a good feel for the subject - it is

practical, interesting, and makes a lot of sens

Approach to the Study

Performing laboratory tests and field tests

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Some suggestions:

WORK HARD

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Some suggestions:

DO NOT WAIT FOR THE LAST MINUTE

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How much soil will deform when it is loaded?

LETS BEGIN------Think about:

When loads are applied, on what rate does soil defo How much load can we apply to soil before it fails?

How does soil fails?

Soil mechanics point of view

Fluid mechanics issues How does water flow through soils? (How fast

How can fluid flow through soil cause it to fail