A Seminar On: Geo-Synthetics

A
Seminar
On
Geo-synthetics
Presented By :
Padarabinda Parida
Regd No : 0501106324
7th Semester
What is geo-synthetic?
A geo-synthetic has been defined by the “American Society for Testing and
Materials (ASTM) Committee D35 on Geo-synthetics” as “A planar product
manufactured from polymeric material used with soil, rock,
earth, or other geotechnical engineering related material as an
integral part of a man-made project, structure, or system.”
Geo synthetics are classified as follows:
1. Geotextiles
2. Geogrids
3. Geonets
4. Geomembranes
5. Geosynthetic clay liners
6. Geocells/geo web members
7. Geofoam
8. Geocomposites
Geotextiles
Geotextiles are defined as “any permeable textile used with foundation soil, rock
earth, or any other geotechnical engineering-related material as an integral part of a
human-made project, structure, or system”.
CHARACTERISTICS
Porous and allow flow of water through it.

Most used geosynthetics.
They may be either woven or non woven
Available in rolls of 5.6m wide and 50-150m long.
Composed of polymers like polypropylene, high density polyethylene, polyster.
Function: Separation, Reinforcement, Filtration, Drainage.
WOVEN GEOTEXTILE
•Uniform and regular interweaving of threads or yarns in two directions.

•Regular Visible Construction Pattern.
•Function: Soil Separation, Reinforcement, Load distribution, Filtration, Drainage
•Have high tensile strength and relatively low strain.
NON WOVEN GEOTEXTILE
Formed by heat bonding, resin bonding or needle punching.

No visible thread pattern.
Function: Soil separation, stabilization, load distribution, but not used for
reinforcement.
They have high strain and stretch considerably under load.
GEOGRIDS
•They have open grid like configuration i.e. they have large aperture
between individual ribs.
•They have Low strain and stretch about 2% under load.
•Strength is more that other common geotextiles.
•Function: Used exclusively for reinforcement
GEONETS
(Geospacers)
•Formed by continuous extrusion of
parallel sets of polymeric ribs(LDPE &
HDPE) at preset angles to one another.
•Their design function is completely
within the in-plane drainage area where
they are used to convey all types of
liquids.
•Though they are used for the drainage
function but they have high tensile
strength.
•Generally used along with one or two
geotextile matter one at the top and other
at the bottom to prevent soil intrusion .
GEOMEMBRANES
•Materials are relatively thin impervious

sheets .
•Generally made from butyl rubber.
•The sell of geomembrane are greater than
geotextiles.
GEOSYNTHETIC CLAY LINERS
•This is the juxta position of polymeric

materials and natural soil.
•Factroy fabricated and betonite clay is
sandwitched between 2 geotextile.
•Structural integrety is obtained by needle
punching.
•Function: Containment,As Hydraulic
barrier.
GEO CELLS/GEO WEB MEMBERS
•Similar to geotextiles or geogrids but have depth.

•Formed by High Density Polyethylene sheets.
•When opened form honey comb like structure and that contain soil,gravel.
•Allow water through it.
•USE: In slopes with soft sub-grade
erosion control in channels
GEO FOAM:
•Large but but extreamly light materials with gas filled cells.
•Made from expanded poly styrene and extruded poly styrene by
polymeric expansion process.
•Function: separation, lightweight fill, compressible inclusions, thermal
insulation,
GEOCOMPOSITES:
•This is a factory fabricated unit with two or more geosynthetic components.

•This is prepared to extract all the major properties of the geosynthetics into
a single unit with minimum cost.
•Along with geosynthetic materials sometimes some non geosynthetic
materials are also used.
The various types of Geocomposites are :-
Geotextile-Geonet Composites
Geotextile –Geomembrane Composiets
Geotextile –Geogrid Composiets
Geomembrane –Geogrid Composite
Geotextile-Polymer Core Composite
FUNCTION OF GEOSYNTHETIC MATERIALS:
A Comparative Review.
Types Of Geosynthetics Separation Reinforcement Filteration Drainage Containment
Geotextile YES YES YES YES
Geogrid YES
Geonet YES
Geomembrane YES
GCL YES
Geofoam YES
Geocomposites YES YES YES YES YES

TESTS ON GEOSYNTHETICS:
1. Grab test
2. Seam testing
3. Puncture test
4. CBR push through test
5. Tear test
6. Diaphragm bursting strength test
7. Cone drop test
8. Dry sieve test
9. Gradient test
CONCLUSION
The rapid growth in the geosynthetic market the
world over has lent confidence to the civil engineer
in their use. One should not be tempted to imagine
geosynthetics are magical materials to yield
excellent results, without due consideration of the
problem or soil geosynthetic interaction. Such a
blind approach could lead to disaster. The future
appears to be more promising with stronger & more
durable geosynthetics emerging into the market
along with fibrous system to be mixed with soil for
giving more hope as well as challenge to the
Geotechnical engineer in the years to come

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A

Porous and allow flow of water through it.

•Uniform and regular interweaving of threads or yarns in two directions.

Formed by heat bonding, resin bonding or needle punching.

•Materials are relatively thin impervious

•This is the juxta position of polymeric

•Similar to geotextiles or geogrids but have depth.

•This is a factory fabricated unit with two or more geosynthetic components.

The various types of Geocomposites are :-

Types Of Geosynthetics Separation Reinforcement Filteration Drainage Containment

Geotextile YES YES YES YES

Geocomposites YES YES YES YES YES

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