Geosynthetics are man-made materials used to improve soil conditions and make possible cost effective environmental, transportation and geotechnical engineering construction projects. This term encompasses permeable textiles, plastic grids, continuous fibres, staple fibres and impermeable membranes etc. Geosynthetics are placed on or in soil to provide one or more of the functions like separation, reinforcement, filtration, drainage or liquid barrier.
There are a number of different Geosynthetic materials currently being used in India.
1.Geotextiles ( Woven / Nonwoven )
2.Geocomposites ( Nonwoven & Geonet composite )
- Geomembrane ( Smooth/Texturised/ Reinforced/Non-reinforced )
4.Geogrid ( Uniaxial: Knitted/Woven )
( Bi-axial : Extruded / Moulded )
- Geosynthetic Clay Liner (GCL)
- Geonet ( In combination with nonwoven one side )
- Prefabricated Vertical Drain (PVD)
- Geobags ( Fabricated from woven /Nonwoven geotextiles)
- Geotubes (Fabricated from woven geotextiles )
- Composite Bags ( Fabricated in combination of woven & nonwoven geotextiles )
- Erosion Control Blankets ( ECB)
- Geostraps ( Single rib polyester coated strap as alternate of geogrid )
- Gabions ( Metal / PP Rope )
Some of the Geosynthetic materials evaluated at BTRA Labs and used in various projects in India are given below:
These are permeable fabric like materials of controlled permeability. They are generally made of polypropylene or polyester fibres; and can classify based on the techniques of production: either woven or non-woven (and knitted for drainage applications).
- Woven geotextiles: Woven geotextiles are typically used for soil separation, reinforcement, load distribution, filtration. They can have high tensile strength and relative low strain or limited elongation under load (typically up to 25%).
Completed projects ( Applications of geotextiles )
Tapi River embankment – State of Gujrat
Raising and strengthening of Retaining wall: Surat
Dredging & Reclamation works : Container Terminal , Mumbai.
Coastal Protection work : Valsad, Surat, Navsari
Flood Protection : State of Gujrat.
RE walls: Barwa Adda Expressway
Laning, Improvement and strengthening of various highways roads: in States like Maharashtra, Tamilnadu, J&K, Gujrat, Jharkhand, and in Karnataka
PP Tape x Tape Geotextiles
Improvement of roads : Kolhapur
- Nonwoven geotextiles: Non-woven geotextiles are typically used for soil separation, stabilization, load distribution, and drainage but not for soil reinforcement such as in retaining walls.
Completed projects ( Applications of geotextiles )
Surface drainage: in Sangli (Maharashtra), New IIT Indore (Madhya Pradesh)
Flood protection: Tapi river bank, Surat (Gujrat)
Separator below bridge foundation: South Centre railway, Vijaywada (Andhra Pradesh)
Water quality improvement: Mindhola River, Surat.
For protection of geomembrane (cushioning) in Landfill: in State of Maharashtra, Gujrat,
Waste Management : Vapi, Gujrat
Geomembranes are impermeable polymeric sheets generally made up of HDPE or LDPE used as barriers for liquid or solid waste containment. They are used in different applications like Water conservation projects, water transport projects, waste treatment projects and landfill projects (dumping ground rehabilitation projects).
Completed projects ( Applications of geomembranes )
Pond liner for raw water reservoir : in Andhra Pradesh, Maharashtra.
Mining Evaporation Pond : for zinc mine in Madhyapradesh
Landfill / Waste management: in State of Maharshtra, Gujrat, Karnataka etc.
Geogrids are stiff or flexible open grid-like structure of integrally connected polymers with large apertures used primarily for stabilization and reinforcement of unstable soil and waste masses.
These Geogrids are of two types Uni-axial Geogrids & Bi-axial Geogrids.
- Uni-Axial Geogrids Mainly Used for Reinforcement Walls & Embankments as in Slope reinforcement, Retaining wall reinforcement, Vegeted retaining walls, Landfill expansion projects and in Railway embankments etc
- Bi-Axial Geogrids Function is to uniformly distribute the loads to the underlying weak strata of low SBC as Reinforcement below the Roads and below foundations.
Completed projects ( Applications of geogrids )
Geogrids( Uniaxial )
Roads and Railway over bridges/ RE walls : in Assam, Bihar, Gujrat, Maharashtra, Tamilnadu, Haryana, Utterpradesh, Andhrapradesh, Rajasthan, Himachal Pradesh, Karnataka and chattisgarh.
Geogrids( Biaxial )
Roads and strengthening of land for ware housing: in State of Maharashtra, Gujrat
Railway track foundation work: Western Railway, Ahmadabad
Glass fibre Geogrids
Extension and strengthening of Airports runways/ Air Force Station : in Jaipur (Rajasthan) and in other States like Gujarat, Maharashtra, Vishakhapattanam and in Hindan, Ghaziabad ( Utter Pradesh ).
Concretization and strengthening: Eastern Express Highway, Mumbai
Geostraps are long belt made of polyester cords and coated with PP. Geostraps are used mainly for Retaining walls as an alternate of geogrids.
Completed projects ( Applications of geostraps)
For construction of fly over bridges/ROB : in Navi Mumbai-Maharashtra, Kannur International Airport Ltd, Kerala, PWD-Puducherri, Chennai , Hydrabad etc.
Geocells are cavity-like materials in a web have ‘depth’. They are meant to contain soil, gravel or other fill material within their maze of cells or pockets and may be porous to allow water movement. They are used on slopes with soft subgrades for stabilization and in erosion control in channels.
Completed projects ( Applications of geocells)
Raw water reservoir for OGT: in Mallavaram, Andhra Pradesh.
Geobags/Geotubes are sand/dredged material made of permeable geotextiles in Tubular or Bag form filled with soil. They are used mostly in flood control, erosion control, bank and costal protection works etc.
Completed projects (Geobags/Geotubes)
Erosion control: in Muzzafar nagar-Shahbazpur road
Pitching & Launching apron bund and restoration of spur: Ghagra River in Ballia District (Utte Pradesh).
Bank protection, Flood management & Erosion Control projects: in Assam
Woven geotextiles tubes
River bank protection : in Lakhimpur Kheri (UP) and in Mohana / Kaoryala River, Haldia dock etc.
Coastal Erosion protection : in Pentha (Odisha)
- Rope Gabion
These are rope/cords made of Polypropylene or Polyester used mostly for Erosion protection and other Engineering applications with in particular structure.
Completed projects (Rope Gabion)
constructing protection wall on mindhola river: Surat (Gujrat)
Protection of B/Dyke from erosion: Brahmaputra River at Dhakuakhana, Assam.
Geotube embankment for coastal erosion protection : Rajnagar of Kendrapara district (Odisha).
Geocomposites are hybrid systems of any, or all, of the above geosynthetic types which can function as specifically designed for use in soil, rock, waste and liquid related problems.
Completed projects ( Geomats )
Geotextile Mattress composite (Upper green nonwoven & black Lower woven Layer) :
Erosion / Flood control: for bank protection and Protection of B/Dyke from the erosion of river in Majuli and at Bramhaputra River, Assam and Bihar.
- Prefabricated Vertical Drains (PVD)
They are band shaped (rectangular shaped) material consisting synthetic geotextile jacket surrounding inner plastic core. Jackets are of non woven polyester or polypropylene geotextile. This is widely used material for Ground Improvement Techniques. The technique is used to advance the consolidation of soft clays / silty clays / silts i.e. to advance the post construction settlements prior to commencement of the actual working loads
Completed projects ( Application of PVD )
Prefabricated Vertical Drain (PVD)
Soil stabilization / ground improvement : for soil consolidation in nhava Sheva (India) gateway terminal-yard, and in Maharashtra Ware House Corporation and chennai metro rail ltd at koyambedu, Haldia ports, Air ports, Harbours in Vishkhapattanam, Western Railways in Maharashtra etc.
Geonets are polymer grids with integrally fused joints and net like structure, manufactured from HDPE/LDPE. These are generally used in drainage application with combination of geotextiles
Foundation of S.W.Drains and Sever lines: Dronagiri (CIDCO, Mumbai)
- Geosynthetic Clay Liner (GCL)
These are the combination of woven and nonwoven geotextiles with Bentonite is sandwiched in between them. The bentonite swell during wet condition and this system is worked as a Clay liner.
Pond liner: in Jammu & Kashmir