Geotextiles is one kind of technical textile. It is defined as any permeable textile material that is used with foundation, soil, rock, earth, etc to increase stability and decrease wind and water erosion. A geotextile may be made of synthetic or natural fibers. In contrast, a geomembrane is a continuous membrane-type liner or barrier Geomembranes must have sufficiently low permeability to control migration of fluid in a constructed project, structure or system. A geotextile is designed to be permeable to allow the flow of fluids through it or in it, and a geomembrane is designed to restrict the fluid flow.
Geotextile use will sometimes mask slope failures until erosion is too far advanced to effectively and cheaply remediate the slope. When advanced erosion is detected it means costly restoration. In contrast when a hydroseeded area has crust failure, whether from weather, human or animal activity, the damage is visible early and can be cheaply repaired.
Erosion control covers a variety of conditions from high velocity stream flow to heavy wave action, to less severe conditions.; All conditions should be considered before selecting a method of control.
Natural fibre geotextiles degrade to form an organic mulch and help in quick establishment of vegetation. Different fibres will degrade at different rates eg coir geotextiles degrade in 2-3 years while jute degrades in 1-2 years. Coir is therefore useful in situations where vegetation will take longer to establish, and jute is useful in low rainfall areas because it absorbs more moisture.
In many arid and semi-arid areas the action of the wind causes considerable erosion. Geotextiles made from natural fibre such as coir, or jute can be used for wind erosion control, dust control, sand dune formation and stabilization. Jute is particularly useful for dust control because of the hairiness of the fibres.
The properties of polymer material are affected by its average molecular weight (MW ) and its statistical distribution. Increasing the average MW results in increasing:
Geotextile use will sometimes mask slope failures until erosion is too far advanced to effectively and cheaply remediate the slope. When advanced erosion is detected it means costly restoration. In contrast when a hydroseeded area has crust failure, whether from weather, human or animal activity, the damage is visible early and can be cheaply repaired.
Erosion control covers a variety of conditions from high velocity stream flow to heavy wave action, to less severe conditions.; All conditions should be considered before selecting a method of control.
Natural fibre geotextiles degrade to form an organic mulch and help in quick establishment of vegetation. Different fibres will degrade at different rates eg coir geotextiles degrade in 2-3 years while jute degrades in 1-2 years. Coir is therefore useful in situations where vegetation will take longer to establish, and jute is useful in low rainfall areas because it absorbs more moisture.
In many arid and semi-arid areas the action of the wind causes considerable erosion. Geotextiles made from natural fibre such as coir, or jute can be used for wind erosion control, dust control, sand dune formation and stabilization. Jute is particularly useful for dust control because of the hairiness of the fibres.
The properties of polymer material are affected by its average molecular weight (MW ) and its statistical distribution. Increasing the average MW results in increasing:
- Tensile strength
- Elongation
- Impact strength
- Stress crack resistance
- Heat resistance
- Increased impact strength
- Decreased stress crack resistance
- Decreased processability
Increasing crystallinity results in:
Separation
Geotextiles function to prevent mutual mixing between 2 layers of soil having different particle sizes or different properties.
Drainage
The function of drainage is to gather water, which is not required functionally by the structure, such as rainwater or surplus water in the soil, and discharge it.
Filtration
Filtration involves the establishment of a stable interface between the drain and the surrounding soil. In all soils water flow will induce the movement of fine particles. Initially a portion of this fraction will be halted at the filter interface; some will be halted within the filter itself while the rest will pass into the drain. The geotextile provides an ideal interface for the creation of a reverse filter in the soil adjacent to the geotextile. The complex needle-punched structure of the geotextile provides for the retention of fine particles without reducing the permeability requirement of the drain.
Reinforcement
Due to their high soil fabric friction coefficient and high tensile strength, heavy grades of geotextiles are used to reinforce earth structures allowing the use of local fill material.
Protection
Erosion of earth embankments by wave action, currents and repeated drawdown is a constant problem requiring the use of non-erodable protection in the form of rock beaching or mattress structures. Beneath these is placed a layer of geotextile to prevent leaching of fine material. The geotextile is easily placed, even under water.
- Increasing stiffness or hardness
- Increasing heat resistance
- Increasing tensile strength
- Increasing modulus
- Increasing chemical resistance
- Decreasing diffusive permeability
- Decreasing elongation or strain at failure
- Decreasing flexibility
- Decreasing impact strengthDecreasing stress crack resistance
Applications of Geotextiles | Uses of Geotextiles
There are at least 80 specific applications area for geotextiles that have been developed.However, the fabric always performs at least one of five discrete functions:
Separation
Geotextiles function to prevent mutual mixing between 2 layers of soil having different particle sizes or different properties.
Drainage
The function of drainage is to gather water, which is not required functionally by the structure, such as rainwater or surplus water in the soil, and discharge it.
Filtration
Filtration involves the establishment of a stable interface between the drain and the surrounding soil. In all soils water flow will induce the movement of fine particles. Initially a portion of this fraction will be halted at the filter interface; some will be halted within the filter itself while the rest will pass into the drain. The geotextile provides an ideal interface for the creation of a reverse filter in the soil adjacent to the geotextile. The complex needle-punched structure of the geotextile provides for the retention of fine particles without reducing the permeability requirement of the drain.
Reinforcement
Due to their high soil fabric friction coefficient and high tensile strength, heavy grades of geotextiles are used to reinforce earth structures allowing the use of local fill material.
Protection
Erosion of earth embankments by wave action, currents and repeated drawdown is a constant problem requiring the use of non-erodable protection in the form of rock beaching or mattress structures. Beneath these is placed a layer of geotextile to prevent leaching of fine material. The geotextile is easily placed, even under water.
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