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Infrastructure is crucially important to foster economic development and prosperity of countries. It contributes to higher productivity and growth, facilitates trade and connectivity, and promotes economic inclusion. The demand for infrastructure development is high.

For quality and for long term sustainability of the infrastructure modern materials are need of the hour. Geosynthetics is one such material family with proven history worldwide. Be it road, railway or any other infrastructure. Awareness of modern day techniques like geo-synthetics is required to improve the quality of the infrastructure and in turn prolong its life.

Geosynthetics are now being increasingly used the world over for every conceivable application in civil engineering, namely, construction of dam, embankments, canals, approach roads, runways, railway embankments, retaining walls, slope protection works, drainage works, river training works, seepage control, etc. due to their inherent qualities.

Geosynthetics are a class of materials used in conjunction with soil to improve the overall performance. In general, they are planar products, made from polymeric material used with soil, rock, earth or other geotechnical engineering-related material, such as fly ash, as an integral part of a project structure or system.

The advantages of using geosynthetic materials include lower repair and maintenance costs, cost-efficiency, design predictability, installation and transportation convenience, quick installation, applicability to a wide range of soils, enhanced performance, extended service life, space savings, good quality control owing to natural homogeneity, increased safety factors, less environmental sensitivity, and compatibility with field conditions.

Roads

Geosynthetics have been successfully used in the construction of roads for decades. They fulfil all the classic functions of drainage, filtration, separation, reinforcement, retaining and erosion control, allowing engineers and road contractors to deliver strong, reliable solutions that will last for many years.

One or more of these multiple functions have been used in at least six important roadway applications. The applications include the migration of reflective cracking in asphalt overlays, separation, stabilization of road bases, stabilization of road soft subgrades, and lateral drainage.

The geosynthetic products most commonly used in roadway systems include geotextiles (woven and non-woven) and geogrids (biaxial and multiaxial), although erosion-control products, geocells, geonets (or geocomposite drainage products) and geomembranes have also been incorporated in a number of applications. These various types of geosynthetics can be used to fulfil one or more specific functions in a variety of roadway applications.

Geosynthetics have made it possible to construct roads and pavements in difficult locations such as marshy stretches, those with soft/ organic deposits and in expansive soil areas. While geosynthetics can be used in the construction of the road itself, they can also be used in retaining soils of steep embankment slopes in areas where right of way is restricted and as reinforced soil walls for bridge approaches. These applications result in significant savings, improved performance and enhanced serviceability on a short-term and long-term basis.

Railways

Geosynthetics can be used effectively in railway application for track bed stabilization, track drainage, erosion control, interface protection, construction over soft soil, steep slope construction, mud pumping, etc.

Its use is a necessity and cost effective for construction of new formations & rehabilitate / strengthen the existing formations for running of heavy axle loads. In railways, high-speed corridors and new technology entail heavy axle loads requiring stable and robust tracks with optimized designs. The significant challenges include ground settlements, weak soil, load distribution, and track line asymmetry or degradation.

The potential use of geosynthetics in the improvement of track stability and reducing the maintenance cost is well established. In railway construction, geosynthetics can be installed within or beneath the ballast or sub-ballast layers, or both. Geosynthetics commonly used in this application are geotextiles, geogrids, geocomposites and geocells.

The reinforcement of the track by means of geogrids provides confinement to the ballast layer, leads to significant reduction in the vertical and lateral deformations, and assures more resilient long-term performance of the ballast layer. The geocomposite provides reinforcement to the ballast layer, as well as filtration and separation functions simultaneously. The use of resilient geogrids and geocomposites beneath the ballast extends the ballast’s life and minimises excessive degradation and deformation, improving sustainability and lowering maintenance/renewal costs significantly.

Non-woven geotextiles are used to divide the ballast and capping layers and also at the contact point between the ballast and capping layers. It acts as a separator and filter, improves drainage and stabilises the capping layer. Geogrids embedded in the track substructure help to mechanically stabilise the capping layer, which is especially important in coastal areas where the subgrade soil is soft and has a limited bearing capacity.

Airports and Ports

Airports face a number of engineering design challenges in order to remain competitive and safe. Geosynthetic materials help in growing capacity and enhancing efficiency without jeopardising safety.

As aircraft manufacturing and design technology progresses, longer and stronger run­ways must be constructed to accommodate the diverse forms and weights of aircraft. Geosynthetics are used in the construction and extension of runways, and for reinforcing pavements. Geosynthetics improve the bearing capacity of soils and strengthen pavements for long-term design life and safer landings.

Geosynthetics are also critical for resolving other airport engineering design issues such as increasing environmental restrictions that require stringent control of rainwater runoff, strict containment of fuel supply, and, where applicable, de-icing facility containment and drainage. Geosynthetics tackle these concerns while also offering more environmentally friendly design options and requiring less long-term upkeep.

Port development and dredging activity also involve the use of geosynthetics. Geotextiles are placed under rock ripraps or precast concrete blocks to prevent coastal erosion. They are also used as silt fences at construction sites to arrest soil particles from runoff water. Geotextile tubes are used in dredging activities while geocontainers are used for the disposal of potentially hazardous dredged materials offshore.

Energy

In coal operations, geosynthetics are primarily used to control environmental contamination such as erosion control materials, silt barriers and sedimentation pond liners. Geosynthetics are also used in mine safety applications, mechanically stabilised earth (MSE) stabilisation berms and the final cover for coal spoil points. Geosynthetics are used by oil and gas corporations to construct paved and unpaved roadways that connect well sites and storage areas. Geomembrane liners are utilised to prevent surface pollution at well sites and as secondary liners for storage tanks and tank farms.

Renewable energy projects involve the use of a variety of geosynthetics, such as geotextiles and geogrids, throughout their construction and operation. Geosynthetics with a high tensile strength are utilised to support and stabilise concrete footings in wind and solar energy installations. Geosynthetics are also utilised to strengthen MSE walls and slopes, providing the flat surface required for these projects. These materials are utilised to line clay reservoirs in hydropower projects. Additionally, geomembranes are employed to line the upstream face of earth fill, concrete and roller compacted dams. Between the dam and the waterproofing geomembranes, geonets, geocomposites and geotextile drainage materials are employed.

Geomembranes, geosynthetic clay liners, drainage geocomposites and geotextiles are used in nuclear power systems to operate double-lined waste disposal systems with leak detecting capabilities. Geomembranes are also utilised as vertical cut-off walls to contain contaminated groundwater seepage and to line disposal containers carrying low-level radioactive waste, such as contaminated equipment, and construction and demolition trash.

Irrigation

Geosynthetics are valuable for developing irrigation and drainage projects, particularly for reducing seepage and erosion. Geosynthetics can be used in the design and construction of dams with low embankments as well as in the long-term management of seepage losses from reservoirs and channels.

Different geosynthetics take on different roles in dam construction and rehabilitation. Geotextiles are used as filters and wrapped drains. Geomembranes find use in rockfill dams, waterproofing, raising embankments, or rehabilitation of concrete and masonry dams. The geocomposites can form a sliding layer for concrete core dams or shaft drains. Geogrids help with the problem of transverse cracking.

Geosynthetics, either alone or in conjunction with a concrete veneer, can greatly increase the effectiveness of a canal lining system. Combination of various Geosynthetics materials in the form of geotextile, geogrids, geomembrane, and geonets are used in lining of irrigation canals to perform the function of drainage, impermeability, filtration etc. They help in minimizing the seepage losses, mitigate pore water pressure being built up beneath lining and reduce water logging related problems.

Tunnels

Tunnel construction has increased in recent years in India, owing to increased emphasis on critical infrastructure projects in the hydro, railway and road sectors.

The two significant roles of geosynthetics in tunnel engineering are drainage and waterproofing. There is extensive use of geomembranes and geotextiles in tunneling.

Geomembranes find extensive use as a liner in hydraulic tunnels. Hydraulic tunnels that convey water are lined with steel, cast in situ, or shotcrete to provide structural stability and prevent water seepage.

Depending on groundwater ingress, transportation tunnels are either waterproofed (sealed) or drained. The entire tunnel behaviour is dependent on the project in question, the surrounding environmental impact, and the handling of groundwater.