3. Geosynthesis
• 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.
These products have a wide range of applications and are
currently used in many civil, geotechnical, transportation,
geo environmental, hydraulic, and
private development applications
including roads, airfields, railroads, embankments, retaining
structures, reservoirs, canals, dams, erosion
control, sediment control, landfill liners, landfill
covers, mining, aquaculture and agriculture.
5. • 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 sub
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 soil's below roads or
structures.
6. APPLICATIONS OF GEO GRIDS
Load is distributed
Evenly After the
use of Geogrid
Geogrid used beneath the Road surface
7. Improvement of sub grade: The
sub grade, which is the most important
load bearing strata, is made solid and
strong by the geogrids.
Reinforcement of pavement
base: The thickness of base if increased
would increase the stiffness of base. The
reinforcement to a given base layer
would give adequate stiffening that helps
in reduction of thickness and time of
construction. This also helps in
increasing the life of the pavement.
8. • Usage of geogrids in retaining
wall construction is in the area of
soil backfills. Holding the soil
together will help in a stable
retaining wall construction. The
soil structural integrity can be
increased by reinforcing it by
geogrids. This help in confining
backfill as well as help in
distributing the loads.
9. GEOTEXTILES
• Geotextiles are permeable fabricswhich 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.
10. TWO TYPES OF GEOTEXTILES
NON WOVEN
Formed by heat bonding,
resin bonding or needle
punching.
No visible thread pattern
Uniform and
regular
interweaving of
threads or yarns in
two directions.
Regular Visible
Construction
Pattern.
WOVEN
11. APPLICATIONS AND FUNCTIONS
• Used in reiforcement of soil.
• Used in soil seperation
• Used in for load distirbution .
• Used in stabalization of soil or land
. Composed of polymers like
polypropylene, high density
polyethylene, polyster. Function:
Separation, Reinforcement, Filtration,
Drainage.
12. GEONETS
• Geonets are also planar products.
• Consists of ribs in two directions.
• Apertures are of diamond shape.
• Thickness is larger than that of geogrids.
• Are also known as “geospacers”.
Geonets are made of stacked, crisscrossing
polymer strands that provide
in-plane drainage.
Two layers of strands are called “biplaner”.
Three layers are called “tri-planar”.
biplaner “tri-planar”.
13. APPLICATIONS
• Erosion control : ribs acts as small
check dams to slow down the
surface runoffs which decrease
erosion potential of water.
Drainage layers: water flows along
the geonets because of
largethickness.
14.
15. GEOMEMEBRANES
• A Geomembrane is very low
permeability synthetic membrane
barrier used to control fluid or gas
migration in a structure, or system.
• Thickness impervious plastic sheet
is 0.5mm to 3mmapproximately.
• Used as a fluid barrier in designing
drainage systems ,etc.
• Used as damp proofcourse in
floors, roofs etc.
18. Geo synthetic clays
• It is a woven fabric-like material,
combination of geotextiles and
geomembranes used as a barrier for liquid
or solid waste
• Applied below and abovegeomembrane
layers in landfills
• Self repair mechanism.
• Provide sub-base support.
19. GEOCELLS
• Geocells are 3-dimensional honeycomb-like
structures, made of strips of polymer sheet.
•Characteristics-
• Similar to geotextiles or geogrids but have
depth.
provides both a physical containment of a
depth of soil and transfer of load through
• Allow water through it.
• Used in slopes with soft sub-grade
• Used in erosion control in channels
22. GEOFOAMS
• Geofoam is manufactured into large lightweight
blocks by polymeric expansion process. They are
large but extremely light materials
• Low density/ high strength: Geofoam is1% to 2% the
density of soil with equal strength.
• Quick to install and can be installed during any type
of weather.
• If geofoam comes in contact with a petroleum
solvent, it will immediately turn into a glue-type
substance, making it unable to support any load.
• Untreated geofoam is a Fire hazard with gas filled
cells.
23. Applications
• Uses-
• within soil embankments built over
soft, weak soils;
• under roads, airfield pavements and
railway track systems subject to
• excessive freeze-thaw conditions.
• thermal insulation in storage tanks
containing cold liquids.
• separation, lightweight fill,
compressible inclusions,
24. GEOCOMPOSITES
• 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-Geonet Composites
• Geotextile –Geomembrane
• Composites
• Geotextile –Geogrid Composites
• Geomembrane –Geogrid Composite
• Geotextile-Polymer Core Composite
25. Advantages
IT is much cheaper than present products used
easy to transport
environmental friendly (does not degrade the soil)
easy to install and use.
improved performance and life exetended
increased in of safety factor
26. Disadvantages
Long-term performance of the particular formulated resin being
used to make the geosynthetic must be assured by using proper
additives including antioxidants, ultraviolet screeners, and fillers.
The exposed lifetime of geosynthetics, being polymeric, is less
than unexposed as when they are soil backfilled.
Clogging or bioclogging of geotextiles, genets, geo pipe and/or
geo composites is a challenging design for certain soil types or
unusual situations. For example, loess soils, fine cohesion less silts,
highly turbid liquids,
Generally require specialized testing evaluations.
Handling, storage, and installation must be assured by careful
quality control and quality assurance.
27. LATESTTRENDS
INPRESENTTIME
• VACCUM CONSOLIDATIONS:Vacuum consolidation (or vacuum preloading) is a
soft soil improvement method that has been successfully used
by geotechnical engineers and specialists of ground improvement companies in
countries such as Australia, China, Korea ,etc.
• ENCASEDSTONECOLUMNS:Stone columns installed in very soft soils will have
very low lateral confinement: hence they undergo excessive bulging, leading to
undue settlement and limited load-carrying capacity. In these situations, the
strength and stiffness of the stone column can be enhanced by encasing the
individual stone columns with a suitable geosynthetic. The encasement improves
load transfer to deeper depths of soil.
• ELECTROKINECTICGEOSYNTHESIS: Electro kinetic geo synthetics (EKG)can be
achieved by combining the electro kinetic phenomena of electro-osmosis,
electrophoresis and associated electro kinetic functions such as electrolysis with
the traditional functions of geo synthetics of drainage, filtration, containment and
reinforcement.
