2. INTRODUCTION
Geosynthetics are materials made from various types of polymers ,
used with geological materials like soil, rock etc. to enhance,
improve or modify the behaviour of various civil engineering works.
Geosynthetics are available in a wide range of forms and materials,
each to suit a slightly different use. These products have a wide range
of applications and are currently used in many geotechnical,
transportation, hydraulic, and private development applications
including roads, airfields, embankments ,retaining structures,
reservoirs, canals, dams, erosion control, sediment control, landfill
covers, mining, and agriculture.
3. Why we use GEOSYNTHETICS
For improving ground stabilization.
Pavements: Roads , Parking Bays , Runways(for bearing
vehicle loads).
Heavy duty pavements : Ports and Harbours.
For railways.
For erosion control.
For retaining wall and bridge abutment.
And most important for building foundation
improvements.
8. Geosynthetics are classified as follows
Geotextiles
Geogrids
Geomembranes
Geosynthetic clay liner
Geofoam
Geocomposites
9. Geotextiles
Geotextiles are permeable fabrics
which when used in association
with soil, have the ability to separate,
filter, reinforce, protect, or drain.
Characteristics-
Porous and allow flow of water
through it.
Most used Geosynthetics.
Available in rolls of 5.6m wide and
50-150m long.
11. Geogrid
A Geogrid is geosynthetic material used to reinforce soils and
similar materials. Geogrids are commonly used to
reinforce retaining walls, as well as sub bases or subsoil's
below roads or structures.
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
14. Geomembranes & Geosynthetic Clay
Liner
A Geomembrane is very low permeability synthetic
membrane barrier used to control fluid or gas migration
in a structure, or system.
Thickness 0.5mm to 3mm
approximately.
Used as a fluid barrier in
designing drainage systems,
etc.
Used as damp proof
course in floors, roofs etc.
15. Geomembranes & GCL’s Functions
Water Conveyance(Canal
Liners) Geomembranes and
GCLs can be economically
employed to reduce the seepage
through unlined irrigation
canals or waterways. They are
effective alternatives to
concrete, asphalt or compacted
clay soils and can be used as an
expedient method to repair
poorly performing existing
linings or those that are rapidly
deteriorating.
16. Geomembranes & GCL’s Functions
Solid Waste Landfill
Containment
Landfill applications
for geomembranes
and geosynthetic clay
liners (GCLs)
include their use as
bottom liners for
waste and leachate
containment, cut-off
walls as well as landfill
closures or covers.
17. Geofoam
Geofoam is used in
geotechnical applications
such as lightweight fill for
construction on soft
ground, for slope
stabilization, and retaining
wall or abutment backfill.
18. Geocomposite
These are combination of two different types of geosynthetics
to take advantage of each.
This is prepared to extract all the major properties of the
geosynthetics into a single unit with minimum cost.
The various types of Geocomposites
are :-
Geotextile –Geomembrane
Composites
Geotextile –Geogrid Composites
Geomembrane –Geogrid Composite
Geotextile-Polymer Core Composite
19. Advantages of Geo-synthetics
Cheaper in product cost, transport and
installation.
Can be designed (predictability)
Can be installed quickly with flexibility to
construct during short period.
Space Savings
Material Quality Control - More
homogeneous than soil and aggregates.
Better Construction Quality Control at site
Easy Material Deployment
20. Usage of Geosynthetics in India
At Delhi Metro
Rail Corporation Ltd
Used for Protection,
Separation, Drainage
between Top Shotcrete
Lining & Yellow
Geomembrane sheet.
21. Usage of Geosynthetics in India
Constructing
Protection
Wall against
sea erosion of
coast at
Kolak,
Gujarat.
23. Usage of Geosynthetics in India
Meghalaya State
ElectricityBoard, Shillong
Function:
• Flexible Earth Retaining
Wall.
• River / Coastal Erosion
Control.
24. Conclusion
It is essential to made the use of Geosynthectics
mandatory in India in order to have increased
efficiency with potential large cost saving, safety of
structures and minimum environmental pollution
including large saving of natural resources
25. References:-
Zornberg, J.G., and Christopher, B.R. (2007). “Chapter 37:
Geosynthetics.” In: The Handbook of Groundwater
Engineering.
Giroud, J. P. (with cooperation of Beech, J.F. and
Khatami, A.). 1993. Geosynthetics Bibliography. Volume
1. IGS, Industrial Fabrics Association International (IFAI)
Publis
Holtz, R. D., Christopher, B. R., and Berg, R. R. 1997.
Geosynthetic Engineering. Bitech Publishers
Ltd.,Richmond, British Columbia, Canada.hers, St. Paul,
MN.
Techfab geosynthetics presented NRRDA,NEW DELHI.