Geotextile can be defined as a permeable textile product that is used to associate with a floor, soil, rocks or other related geotechnical engeering materials in civil engineering or other relating constructions. In recent years, its use has been increasing.
There are two basic forms of geotextile. They are woven and nonwoven geotextiles. Apart from these, there are needle punched, heat and chemical bonded special forms of geotextiles.
Geotextiles have more than 100 special application areas. Geotextiles are used according to six fuctions that are written below. They are:
Insulation (in reinforcement of layers of asphalt, impregnated with betumen)
Nowadays, the most important use of geogrid is reinforcement. Although there are many different methods, materials and approaches in ground reinforcement, the use of geogrid in this field is increasing fast. The most important feature of the geogrids is so called hole/spacing, the spaces between the transverse and longitudinal strips that are wide enough to allow to ground pass through.
Due to the improvements in required methods for preparation of polymer metarial with high deformation modules, especially the improvements for cold processing, have made this product suitable to use as a reinforce product.
In addition to the strength of the strips of the geogrids, bond strengths are also important. Because the geogrids allow the floor to pass through the holes, a passive strength is formed in the transverse strips which perpendicular longitudinal strips to which the load is applied. At the same time, geogrid is connected to the ground through these strips.
Use of geogrids;
- On uncoated roads, below aggregate,
- Under the ballast layer in railway construction,
- Under temporary construction areas or surcharges,
- Strengthening of landfills and filling dams,
- Repair of slope renovations and landslides,
- In gabion formation in wall constructions,
- In gabion formation in erosion control structures,
- In the formation of gabions in bridge legs,
- As a basic reinforcement on karstic areas,
- As a reinforcement between the tops of the pile foundations,
- As a bridge between broken or cracked rocks,
- As coating on soft floors,
- As coating on swamp and tundra,
- Anchor plate for retaining wall surface panels,
- Asphalt reinforcement in coatings,
- Strengthening of differential rock areas,
- Strengthening of differential concrete areas,
- As intermediate material between geotextiles,
- As intermediate material between the geomembranes,
- As Intermediate material between geotextile and geomembrane,
- As basis reinforcement on soft floors,
- Strengthening of soil fillings allowed to be vertical expansion;
- Strengthening of soil fillings allowed to be horizontal expansion;
- As three-dimensional coating for the bearing strength of soil fills,
- As a three-dimensional coating for soil fillings on soft soils.
Geonets are similar to grid materials and can be applied under geogrids. Its use here provides this feature, although it is not intended to isolate the area. Where geogrids are used as reinforcement, geonets are used to provide planar drainage. In this case, Geonets do not mean that they are weak and unstable materials, although they are not used for reinforcement purposes.
Although they have a certain strength, they are generally used for drainage purposes. Using geonets, geomembrane or other material on the top or bottom of the material, they enter the ground’s voids and prevent the material from losing its drainage property. Therefore, they are used in the preparation of composite materials.
- For the purpose of water drainage behind retaining walls,
- For the drainage of water leaking from the rock slopes,
- In order to drain the water that has leaked from the floors,
- For the purpose of water drainage under the sports fields,
- For water drainage on frost-sensitive floors,
- For water drainage under building foundations,
- For the drainage of dirty water under the motorways,
- In sub-drainage systems under soil fillings,
- Drain covers under surcharges.
Nowadays, different types of synthetic rubber materials have become an important industrial product. It is made of original geomembrane rubber and used as a coating material in potable water pools. These materials become soft and flexible when heated, but do not change their inner properties, and then return to their original characteristics when they are cooled.
Geomembranes are mainly used to ensure impermeability. Impermeability in field applications is also due to geomembranes.
The use of geomembranes in environmental, geotechnical, hydraulic and transportation fields;
- As coating material for potable water,
- As coating material for water tanks,
- As coating material for liquid wastes,
- As coating material for radioactive and hazardous liquid wastes,
- As secondary coating material for underground storage tanks,
- As coating material for salt water solutions,
- As coating material for water channels,
- As coating material for various waste water channels,
- As coating material for solid waste sites,
- In order to prevent leakage within the zoned embankment dams,
- In coating of hazardous filled channels
- To ensure impermeability within the tunnels,
- To ensure impermeability of rockfill dams
- To ensure impermeability of masonry dams,
- In the control of the leak inside the bumpers,
- Prevention of odor from fills,
- As a barrier against vapor under buildings,
- In control of swelling floors,
- In the control of frozen delicate grounds,
- In order to prevent water leakage in sensitive areas,
- Keeping of harmful liquid wastes that may occur under and near the motorways,
- As coating element for temporary surcharges,
- As a sealing layer under asphalt pavement coatings,
- In order to ensure sealing in the above ground storages.
Geosynthetic clay coatings were first used in a solid waste collection center. This product consists of a mixture of bentonite clay between two geotextiles.
Geosynthetic clay coatings; They are also called “clay liners”, bentonite liners“, “bentonite mats”, and “prefabricated bentonite clay liners“.
Geosynthetic clay coatings are used as a hydraulic barrier against water and other liquid materials. As a hydraulic barrier, geosynthetic clay coatings can be used instead of compressed clay layers.
The main advantages of geosynthetic clay coatings are; limited thickness, to reduce the different settlements under its ground or on the waste material, easy placement and low cost.
Usage areas of geosynthetic clay coatings;
- In fillings, as the first coating layer under geomembranes,
- In fillings, as a secondary coating layer under geomembranes,
- In fillings, under geomembranes and above clay layers (in three-component layers)
- In vertical stud curtains, adjacent to geomembrane,
- As a layer of protection against geomembranes, rough aggregates,
- As a second coating layer in underground storage,
- In the formation of dam to surface waters,
- In the formation of dam to surface waters, as a composite coating under geomembranes,
- In water pools, as a composite coating under water in geomembranes.
Classical materials used in pipelines during transportation of water, gas, oil and various other liquid materials are steel, font, concrete and clay. These pipe materials are classified as rigid due to their behavior. Tubes made of polymeric materials are classified as flexible.
Plastic pipes are the first products made of polymer material and have a wide range of applications. Usage areas; industry, agriculture, transportation and drainage applications.
- As edge drain in highway, railway and airports,
- As seepage drains in tunnels,
- As pore water drain behind retaining walls,
- As interception drain for leakage of ground and rock slopes,
- As interception drain for leakage in groundwater,
- As pipes in drainage projects
- In between gravity and fluid transport lines,
- In force transmission lines under pressure,
- In waste water drainage systems,
- In the pipelines where the chemicals are transported,
- For the removal of water in the ground and waste material fillings.
Today, in the construction sector, creative projects are produced to meet the increasing needs and new products are required to implement these projects. These developments in the construction sector made it necessary to diversify the geosynthetics used and to offer different solutions. Geocomposites are also used to meet these needs. Using different properties of different materials, we try to find the most suitable solutions for the problems. Geocomposites are generally composed of various combinations of geosynthetic materials. In some cases, non-synthetic materials and geosynthetics can be used to provide appropriate solutions and low costs. Geocomposites consist of combinations of many products.
Geocomposites have a large number of applications; but generally geocomposites are used with the following four functions. These functions,
Briefly, it is the general name of all kinds of foam materials used in geotechnical engineering applications. A further definition is a material which is obtained by means of expansion, resulting in the formation of a variety of closed and internal gas-filled cells. Cell walls are solid but permeable to gases.
Geofoam is now worldwide accepted as as a geosynthetic product, such as geotextile, geomembrane etc..
Many geofoam materials are based on polymeric (plastic) or glassy foam. There are two types of polystyrene foam:
- EPS (Expanded polystyrene)
- XPS (Compressed polystyrene)
In the fillings on soft and weak soils, where the freezing-dissolution effect is very effective, geofoam is used in areas such as underneath roads, airport coatings and railways etc.
Geotubes are capsule shaped elements which are formed by putting together the geotextile rolls and have the strength to hold a relatively large amount of water-saturated material. The geotextile tubes have a porous structure and the solid part is retained when filled with a water-saturated material or slurry, and the water is filtered out of the pores of the geotextile forming the geotube. Geotubes have also been developed for erosion control and storage purposes.
Geotextile bag, tube and carrier, varying in size from 1 m3 to 3000 m3, are a wide variety of infills. These filled elements or tubes are used in the manufacture of stability pads, which are formed under water, in the arbitration of coastal structures against waves, in control of the thalweg erosion by berms, in the protection of the bridge edge legs against the erosion, in the storage of the material from the bottom sweep and in the storage of clean or contaminated materials.
Screened material, domestic and industrial wastewater treatment sludge, animal waste, paper mill sludge, fly ash, mineral waste
Airports, highways, oil spills, agricultural operations
Structural Erosion Prevention
Berms, beaches, rivers, swamps, silt retainers
Fine-grained screened material, contaminated screened material, sealing of the contaminated material
As mentioned above, there are many uses of geotubes and the usage areas of geotubes are increased due to the increase in technical characteristics. Geotube has field applications to prevent structural erosion.
Dewatering with geotube is a three-step method.
In the first stage, high strength geotubes made of geotextile having the ability to hold larger grains of specific diameter are filled with waste sludge, contaminated floor or waste material obtained by screening. The structure of the geotextile in which the geotube is manufactured should be suitable for the grain structure of the material to be filled and keep the sediment to a great extent within the geotube.
In the dewatering stage, excess water is discharged from the geotube. The discharged water is generally of a quality that can be reused or returned to the natural environment without further improvement. As the amount of solid material retained in the geotube increases, the quality of discharged water is further increased.
In the final stage, during the consolidation phase, the waste water evaporates from the texture of the geotube and the density of the material in the interior increases and consolidates.
Geocell retainer systems are three dimensional honeycomb style elements filled with ground, rock or concrete. These systems are generally called geocell, which are produced from strip-shaped polymer layers or geotextiles, are placed diagonally and are secured to each other at the intersection points. These strips are turned into a wide honeycomb cover when they are pulled.
They are used as barrier and protection elements required for slope, channel or ground stabilization.
Due to the development of materials used in geosynthetic products, the number of existing products is rapidly increasing. Due to the new products, both safe and economical solutions are obtained. Polymeric anchors, wrapped floor cells etc. products can be called as geo others.
As a result, since they are geosynthetic materials, they have properties such as seperation, strengthening, filtration, drainage.