Geo-synthetics

1. TECHNICAL SEMINAR
ON
GEOSYNTHETICS
S.SRINIVASREDDY
14H51A01A4

2. What Are Geosynthetics?
• A planar, polymeric (synthetic or natural) material used in contact with
soil/rock and/or any other geotechnical material, for Filtration, Drainage,
Separation, Reinforcement, Protection, Sealing and Packing
GEOSYNTHETICSPERMEABLE
IMPERMEABLE
GEOTEXTILE GEOMEMBRANE

3. GEOTEXTILES :
Any permeable textile natural or synthetic, used with foundation soil, rock, earth, or
any other geotechnical engineering related material
History of Geotextiles in India
• Used commercially since early ’80s
• However, during ’80 – ’90 the use was restricted to separation, filtration and drainage
application for both non-woven and woven type
• Indian manufacturer like Hitkari, Tata Mills etc. participated in production of non-woven
type for civil engineering application
• Application in river Training works and erosion control also started
• National Highways saw the application in drainage, embankment protection, base course
stabilization and separation below highway embankments, also protection against erosion.
• Growing usage for environmental projects such as landfills, waste storage etc.
• Now there are non-woven as well as woven Geotextile manufacturer besides several
unorganized participations

4. Types of Geotextile
1.Non-woven
2.Woven
3.knitted fabrics :
(rarely used as geotextiles.)
WOVEN NON WOVEN
Separation Separation
Reinforcement Filtration
Impermeable Permeable
Referred by strength Referred by weight
ex:furniture fabrics ex :medical garmnets,hazmat
clothing
Areas of application of Geotextiles :
Flexible paved road construction
Drainage applications
Pavement overlays
Function of geotextiles:
service life of roads
load carrying capacity
rutting overlays

6. • Mechanical properties of geotextiles

9. GEOMEMBRANE
• Geomembranes are thin 2D sheet of materials with a very low
permeability.
• These are subjected to very small amount of seepage ass a result of
permeation.
• Geomembranes are made up of materials like PVC,CPE etc.
• Geomembrane width is not more than 2mm and thickness of 0.5-2.55mm
• Membranes are reinforced with bitumen may be of 4-5M wide with
thickness of 1.5-6mm.

10. Geosynthetics are classified as follows :
• Geotextiles
• Geogrids
• Geonets
• Geomembrane
• Geocells
• Geofoam
• Geocomposites

11. Geogrids
• A planar, polymeric structure consisting of a regular open network
of integrally connected tensile elements, which may be linked by
extrusion, bonding or interlacing, whose openings are larger than the
constituents, used in contact with soil/rock and/or any other
geotechnical material in civil engineering applications.
Use of grogrid for soil reinforcement
Use of grogrid in grass lanes

12. Geonet
• A planar, polymeric structure consisting of a regular DENSE network,
whose constituent elements are linked by knots or extrusions and whose
openings are much larger than the constituents, used in contact with soil
rock and /or any other geotechnical material in civil engineering
applications

13. GEOCELLS:
Geocells are 3-dimensional honeycomb-like structures, made of strips of
polymer sheet.
Similar to geotextiles or geogrids but have depth
It is used in erosion control

14. Geosynthetics – the functions
• Separation
• Drainage
• Filtration
• Reinforcement
• Moisture barrier
• Cushion

15. Materials used for Geosynthetics
• Polyamide
• Polyester
• Polyethylene
• Polypropylene
• Polyvinylchloride
• Chlorinated polyethylene

16. BENEFITS OF GEOSYNTHETIC REINFORCEMENT
1 PAVEMENT SYSTEMS
1.1 BASE/SUBGRADE
2 EMBANKMENTS OVER SOFT SOILS
3 SLOPES AND WALLS
1.Pavement systems :
c

17. 1.1 BASE AND SUB-BASE REINFORCEMENT
The use of a geosynthetic placed as a tensile element at the bottom or
within a flexible pavement base or sub-base to :
• increase the service life
• obtain equivalent performance with a reduced structural section
• avoid subsidence problems (sinkholes)
Applications:
• Permanents ways
• Parking lots
• Airport taxiways
• Container loading facilities
• Railway tracks

18. 2 EMBANKMENTS OVER SOFT SOILS
Basal reinforcement
Piled embankments with basal reinforcement

19. 3. SLOPES AND WALLS
TYPES (angel of inclination larger than 80degrees)
i. STEEP SLOPES
ii. BLOCK WALLS
Steep slopes
Block wallsbenefits
Economical solutions
Rapid and simple construction method
Allows construction in difficult terrain
Allows use of cheaper fill material
Satisfactory appearance structures
Environmental:
reduce damaged areas and
reduce natural material extracting
Reinforcement spacing

20. Applications of geosynthetics
• Unpaved roads
• Separation
• Reinforcement
• Filtration
• Drainage
• Moisture barrier (when impregnated)
• Hydropower construction
• Environmental engineering
• Railway construction
• Road construction
• At seaports and
• airports Mine construction In urban construction

21. WORLD MARKET FOR GEOSYNTHETICS
• World Geosynthetics to 2013 – Global demand for geosynthetics is
projected to increase 5.3 percent annually through 2013. China will account
for the largest share of new global demand as it continues to develop large-
scale infrastructure and erosion control projects. North America will remain
the second largest regional market. Geogrids will achieve the fastest gains

22. CONCLUSION
It is expected that the use of geosynthetics will become increasingly
routine, and that geosynthetics will be the standard material of choice for
several applications. Use of geosynthetics in pavement structures (to
perform the functions of separation, filtration, drainage, and reinforcement)
should increase significantly in the new millennium as the benefits of these
materials are quantified. In addition, the versatility and usage of
geosynthetics will be enhanced with the development and adoption of in
situ and rapid soil testing procedures

23. REFERENCE :
• Properties and materials -GIT textbook chapter 8 by P.Purushothama raj
• Geosynthetics introduction by DR.G.Venkatappa Rao
• Images ,tables: Google images
• Introduction : Wikipedia
• History of geotextiles : slide share

24. THANK YOU