CE 100: Introduction to Civil and Environmental Engineering

Geotechnical Engineering

Nov 3rd 2013

Lecture 7

What is Geotechnical Engineering?

Geotechnical engineering involves investigation and engineering evaluation of

-materials, -their systems-structural foundations and -other civil engineering works.

It also involves applications of the -principles of the soil mechanics - construction techniques and -performance evaluation of civil engineering work

influenced by earth materials.

It requires comprehensive understanding of the elements of geologic environment.

Which type of information is needed in Geotechnical Engineering?

• Nature and composition of Soil and rock. • Ground water condition • Soil stresses:

– stress history, over-consolidation, lateral stresses. • Confined compression of soils. • Soil suction, collapse and swelling. • Soil strength and deformability:

GEOTECHNICAL APPLICATIONSFoundations

Retaining walls

Earthern Dams

Concrete Dams

Geomembrane/geosynthetics

Trenchless technology

GEOTECHNICAL APPLICATIONS

Foundation Engineering– Foundation engineering is an art ofselecting, designing and constructing the elementsthat transfer the weight of structure to theunderlying soil or rock.

– Before designing a foundation, the engineer must have a reasonably accurate conception of

the physical properties and

the arrangement of the underlying materials.

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Retaining Walls~ for retaining soils from spreading laterally

Road

Train

retaining wall

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Earth Dams~ for impounding water

soil

reservoirclay core shell

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Concrete Dams

reservoir

soil

concrete dam

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Concrete Dams

Three Gorges Dam, Hong Kong

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Sheet Piles~ resist lateral earth pressures

~ used in excavations, waterfront structures, ..

~ in temporary works

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Geofabrics~ used for reinforcement, separation, filtration and drainage in roads, retaining walls, embankments…

Geofabrics used on Pacific Highway

Geosynthetics/Geomembrane

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Geosynthetics/Geomembrane

Waste Disposal in Landfills

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Reinforced Earth Walls~ using geofabrics to strengthen the soil

Trenchless Technology

http://nastt-bc.org/content/listing-trenchless-technology-pictures