Geotextile is a synthetic permeable textile material used to improve the soil characteristics. It has the ability to separate, filter, reinforce, protect and drain when used in association with soils. Geotextiles are ideal materials for many infrastructure works such as roads, , landfills, drainage structures, and other civil projects.
Types of Geotextile
Geotextiles are made up of polymers such as polyester or polypropylene. They are divided into 3 categories on the basis of the way they are prepared :
1) Woven Fabric Geotextiles
2) Non-Woven Geotextiles
3) Knitted Geotextiles
- Woven Fabric Geotextile
Commonly found geotextiles are of the woven type and are manufactured by adopting the techniques which are similar to weaving usual clothing textiles. This type has the characteristic appearance of two sets of parallel threads or yarns. The yarn running along the length is called warp and the one perpendicular is called weft.
- Non-Woven Geotextile
Non-woven geotextiles manufactured from either continuous filament yarn or short staple . The bonding of fibers is done using thermal, chemical or mechanical techniques or a combination of techniques.
Geo-fibers obtained from mechanical interlocking or chemical or thermal bonding have a thickness of 0.5-1 mm while chemically bonded non-wovens are comparatively thick usually in the order of 3 mm.
- Knitted Geotextile
Knitted geotextiles are manufactured by the process of interlocking a series of loops of yarn together. All of the knitted geosynthetics are formed by using the knitting technique in conjunction with some other method of geosynthetics manufacture, such as weaving.
Apart from these three geotextiles, other geosynthetics used are geonets, geogrids, geo-cells, geomembranes, geocomposites, etc. each having their own distinct features and uses for special applications.
Recommended Read:Geosynthetics in Civil Engineering and Construction Works
Functions of Geotextiles
The mode of operation of a geotextile in any application is defined by six discrete functions :
- Separation
The separation function of geotextile is majorly used in the construction of roads. Geotextile prevents the intermixing of two adjacent soils. For example, by separating fine subgrade soil from the aggregates of the base course, the geotextile preserves the drainage and the strength characteristics of the aggregate material.
Some of the applicable areas are:
Between subgrade and stone base in unpaved and paved roads and airfields.
Between subgrade in railroads.
Between landfills and stone base courses.
Between geomembranes and sand drainage layers.
- Filtration
The equilibrium of geotextile-to-soil system that allows for adequate liquid flow with limited soil loss across the plane of the geotextile. Porosity and permeability are the major properties of geotextiles which involve infiltration action.
A common application illustrating the filtration function is the use of a geotextile in a pavement edge drain, as shown in the figure above.
- Reinforcement
Introduction of geotextile in the soil increases the tensile strength of the soil the same amount steel does in concrete. The strength gain in soil due to the introduction of geotextile is by the following 3 mechanisms :
Lateral restraint through interfacial friction between geotextile and soil/aggregate.
Forcing the potential bearing surface failure plane to develop an alternate higher shear strength surface.
Membrane type of support of the wheel loads.
- Sealing
A layer of non-woven geotextile is impregnated in between existing and new asphalt layers. The geotextile absorbs asphalt to become a waterproofing membrane minimising flow of water into the pavement structure.
Uses of Geotextile in Construction
The scope of geotextile in the engineering field is very vast. The application of geotextile is given under the heading of the nature of work.
1.Road works
Geotextiles are widely used in the construction of the road. It reinforces the soil by adding tensile strength to it. It is used as a rapid de-watering layer in the roadbed, the geotextiles need to preserve its permeability without losing its separating functions.
- Railway Works
The woven fabrics or the non-woven ones are used to separate the soil from the sub-soil without impeding the groundwater circulation where the ground is unstable. Enveloping individual layers with fabric prevents the material from wandering off sideways due to shocks and vibrations from running trains.
- Agriculture
It is used for mud control. For the improvement of muddy paths and trails those used by cattle or light traffic, nonwoven fabrics are used and are folded by overlapping to include the pipe or a mass of grit.
- Drainage
The use of geotextiles to filter the soil and a more or less single size granular material to transport water is increasingly seen as a technically and commercially viable alternative to the conventional systems. Geotextiles perform the filtering mechanism for drainages in earth dams, in roads and highways, in reservoirs, behind retaining walls, deep drainage trenches, and agriculture.
River, Canals and Coastal Works
Geotextiles protect river banks from erosion due to currents or lapping. When used in conjunction with natural or artificial enrockments, they act as a filter.
Functions of arian khak geotextile
Among the most important functions of geotextile in the construction industry, the following can be mentioned:
Drainage, protection, erosion control, separation, filtration and reinforcement
Geotextile has many applications due to its roles:
The role of isolation on the road
covered road
Road infrastructure
Railway infrastructure
Straps
Erosion control
Protective walls
Underground drainage, behind retaining wall, columns and vertical surface
Waste control and maintenance
Liquid and gas collection system
Geomembrane protection
Stability and stabilization of lines
Protection and drainage systems under artificial grass
Covering and isolating tunnels
Exploitation of swamp lands
Earthquake resistance
Filters in irrigation canals
Filtration in earth dams
Reinforcement
Protection of the banks of rivers and seas
Tanks and elephants in isolated tunnels
Water and chemical storage tanks
Consolidation of the bed of embankments and artificial slopes
Construction of the airport embankment
The role of isolation on the road
The main cause of road failure is the injection of adjacent layers to the gravel foundation, and its message is the reduction of resistance in the gravel layer. When the gravel layer is placed on the underlying layer, the underlying layer is contaminated with soil and under the traffic load and vibration of the gravel layer. It injects the soil grains into the soil and causes the layer to move upwards, in the discharge areas it causes the weak underlying soils to be pumped into the sands and all these conditions reduce the thickness of the layers and as a result, the layer Blocked road support becomes vulnerable and road life is reduced.
The use of geotextile to improve the performance of highways, unpaved roads, parking lots, airports and loading docks has been proposed as one of the cases.
Road infrastructure
In this application, geotextile is used in one or more main roles according to the location conditions, in the separation between the underlying layer and stone materials and grains. It will pass by itself. And it prevents the passage of soft soil to the stone layer of the foundation and drainage layers. In the role of strengthening, it strengthens the soft material of the sub. And it increases the amount of CBR to the optimum level, and by increasing regional and local pressure, it prevents rock materials and grains from sinking into the soft bed, and also improves the role of road drainage.
covered road
The main source of destruction in road pavement is the unwanted water injection into the structure through cracks in the road surface. During road pavement construction or development, the addition of geotextile between the adhesive overlay and the new asphalt layer creates sodium and the roof foundation. Supports against the subsurface.
Straps
Using geotextile in the field of dam construction for waterproofing and preventing water from settling in the dam body and preventing its destruction. In this application, heavy geotextile is used as the protective layer of the geomembrane membrane. It also acts as a surface drain of the dam wall and transfer to the lower drains of the dam.
Railway infrastructure
Geotextile in this application stabilizes the railway line. Maintaining the geometry of the railway bed and acting as a separator between the foundation and sub-ballast materials, as well as restraining the foundation and sub-foundation materials against lateral movements, helps. The geotextile also provides a mechanism for lateral (margin) drainage and improves drainage performance.
Erosion control
Geotextiles are used in areas such as drainage, embankments, protection systems and piers, as well as for permanent erosion control similar to underground drainage. Without a geotextile filter, water waves erode the underlying materials under the rip-rap stone cover or reinforced concrete.
Protective walls
Geotextiles are widely used to strengthen embankments in soft soils, dams and retaining walls. In fact, the geotextile used for a retaining wall can be made for about half the cost of a traditional retaining wall.
Waste management control
Underground drainage
Geotextile replaces conventional soil filters for drainage covering all structures from groundwater control systems to road pavements, dam infrastructure and walls. Light to medium weight nonwoven geotextiles are suitable for drainage filter applications, allowing groundwater to pass through the drainage cores while preventing the drainage system from clogging with adjacent soil.
Liquid and gas collection system
Non-woven geotextiles are used for liquid and dissolved gas collection systems.
Vertical drains are columns or trenches made of permeable materials that are built to increase the pore water pressure of saturated sandy and loose clay soils to reduce the possibility of liquefaction and impact. The proposed model is semi-prefabricated geotextile drains, which after digging the soil by drilling machines, geotextile layers are placed in the cut and filled with soil grains. Among the advantages of this method, we can mention low payment, fast installation, improvement of mechanical properties of the soil during compaction and reduction of liquefaction, reliable continuity of drainage, high permeability, slight disturbance of soil and proper drainage.
Filter in water channels
This application is the most well-known and widely used application of geotextile. In this process, the geotextile is placed in contact with the soil that is supposed to be drained. Geotextiles actually replace sand materials and should have the same performance and efficiency as sand filters. Both geotextile and sand filters must pass gas water without creating any kind of hydrostatic pressure.
Filtering in earthen dams
The filter is one of the important components of the earthen structures that are related to the flow of water. When it becomes from the soil with relatively small grains to the coarse material, the material may move from its place, first of all, it causes instability. the entire structure and create a danger, and secondly, make the empty spaces of the drainage system and prevent the movement of water, and as a result, increase the hydrostatic pressure in the structure.
Advantages of Arin Hak geotextile
From the total population of geotextiles, we can mention quick construction and installation, economic efficiency, chemical resistance, high durability, lack of separation between grains that occurs in granular filters, and reducing the amount of drilling. The thickness of the geotextile layer is much smaller than the grain material layer, and this is important from the economic and operational point of view. The price and cost of geotextile is generally lower compared to other drainage system materials.
Arin Khak company with years of experience in the field of geotextile is ready to cooperate with you, dear ones, contact our consultants for free consultation.
