Geotextile || Functions || Applications

Use of Textile in Construction works

Geotextiles are defined as planar material or product which is manufactured from polymeric material and is used with soil, earth or rock or other geotechnical engineering related material as an important part of a human made project or system.  

Reasons for acceptance by Civil Engineers:
  • Used in increasing tensile strength of soil as soil itself does not posses tensile strength.
  • Secondly, it is useful in layered construction of pavements, retaining walls and foundations. Also, they are flexible in nature

Major functions of Geotextiles:
Reinforcement: It provides strength to soil that is weak in tension and posses no tensile strength of its own.

Separation: The main role of separation is to prevent intermixing of two dissimilar materials as intermixing of stone and fine soil affects the drainage and strength of the stones.
Applications: In roadways, below embankment fill and soft foundation spill and below rail ballast.

Drainage: The main function is to transfer the liquid with in the plane of Geotextiles. Mainly non-woven Geotextiles, geonets and geocomposites are used.
Application: Around trench drains and edge drains, behind retaining walls and bridges and for slope stabilization.

Filtration: Allows flow of liquids from soil across the plane of geotextile, retain soil particles and avoid clogging. Geocomposites are used for this purpose.
Erosion: Prevents washing off of the upper layer of the soil due to wind forces. Geomats, geocells, bionets are used for the same.

Classification of Geosynthetic:
Woven or non-woven Geotextiles:
Woven Geotextiles: Posses high tensile strength and relatively low strain.
Functions: load distribution, separation and reinforcement.

Non-woven Geotextiles: High strain and stretch considerably under load.
Function: Major function includes filtration and drainage.

Can be woven, non-woven or knitted, mechanical and hydraulic properties vary widely.
Application: Used for separation, drainage, reinforcement.

Geogrids are open grid like configuration having large apertures, can be have both unidirectional or bidirectional properties. Have more strength but low strain.
Application: Reinforcement applications

Combines attributes of two or more materials to serve specific application
Factory fabricated unit with two or more geosynthetic components.

Geomembranes are basically impervious polymeric sheets which are manufactured for containment purpose
Application: linings, covers for solid storage facilities etc.

Geosynthetic Clay liners (GCLs)
They are fabricated rolls of bentonite clay sandwiched between two geosynthetic products
Application: used in environmental and containment applications.

Flexible forms of geotextiles generally used for containment for pollutant sediments present in water bodies
Applications: Coal sludge, municipal sludge etc.

Plastic pipes subjected to high compressive loads. They are smooth walled or corrugated
Application: Drainage

Geotextile properties:
Intrinsic physical properties:
Tensile strength: It is important for all geotextile functions and installations

Compressibility: It reduces transmissivity and permittivity as the pore structure changes
Seam strength, tear strength, burst strength, impact strength and puncture strength

Mechanical Properties:
  • Shear strength depends on the friction between soil and geotextile
  • Tests performed are direct shear test and pullout tests

Endurance properties:
  • Abrasion: wearing of material by rubbing actions against large soil particles
  • Creep: It refer to the elongation of the material
  • Clogging, UV degradation and chemical, biological degradation.

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