High on Adaptability

With the entry of new technology, ma­terials and processes in the Indian construction industry, geosynthetics is gaining traction as a construction material across a wide range of civil engineering fields. One of the main reasons driving this growth is the thriving market in India.

Infrastructure is critical to India’s growth and development. The Indian government has placed emphasis on infrastructure expansion through constant budget allocations and promotion of foreign direct investment (FDI) in the sector. According to the government, the UDAN project aims to build over 100 airports by 2025, which will also provide a considerable boost to the geosynthetics industry. The 100 Smart Cities Project, the Bharatmala Project, Housing for All by 2022, dedicated freight corridors, and the Narmada Valley Development Project are some of the ongoing government programmes that will contribute to the growth of the geosynthetics industry. Moreover, STRATA Systems, Inc. had launched a production facility in India in February 2019 to meet the expanding global demand for geosynthetic products. The government is increasing its in­vestment in housing, safe drinking water, he­alth­care infrastructure, educational institutes, railways, airports, bus terminals, metro, irrigation projects and dam construction, among ot­h­­er things, and it is encouraging the use of geo­synthetics for enhanced strength. Thus, more government support will bolster the geo­sy­nthetics business and contribute to the industry’s growth.

Applications

Geosynthetics are being used for all conceivable situations in civil engineering and infrastructure projects – roads and expressways, airport runways, embankments for railways, dams, canals, flyover embankments, seaside platforms, retaining walls, etc.

Roadways: Geotextiles, which are permeable textile materials consisting of polypropylene or polyester, are required for road construction. The road sector is the major user of geosynthe­tics, primarily geogrids. It is used in road works for creating slopes/slope rehabilitation, widening pavements, erosion control, filtration and drainage. Notably, 70-80 per cent of the geo­grid market is for the road sector, and the rest is used in coastal erosion, railways, airports and tunnels. As per industry estimates, every 15-20 km of road length under the NHDP has at least one elevated structure. According to industry experts, 5,000-10,000 sq.m. of geogrid is required for each of these structures.

The progress of the geosynthetics sector over the past four decades has aided in the development of approaches for optimising the overall performance of paved roads. At the intersection of the granular base course and the soft soil subgrade, the layers of geosynthetic components are employed during the construction of paved roads. Geosynthetics are critical in the development of paved roads be­cause they operate as a separator by generating capillary gaps that mitigate frost activity in frost-prone soils. Geosynthetics are also often used in airport pavements and parking lots due to their improved performance compared to asphalt roadways.

Railways: Geosynthetics are extensively accep­ted and employed by Indian Railways for a variety of purposes, including ground improveme­nt, base stability for steep embankments over soft soil, track bed stabilisation, track dra­in­age, steep slope stabilisation and erosion ma­na­gement. Geosynthetics result in significant cost reductions and enhanced performance over the short and long term.

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. For instance, Polypropylene biaxial geogrid (TechGrid PP) is the ideal solution for reducing ballast degradation and preventing track bed settling in railways. The incorporation of PP biaxial geogrid within a layer of granular material results in strong contact, mostly by particle interlocking within the PP biaxial geo­grid apertures, which results in greatly inc­rea­sed structural capacity.

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.

Maintaining adequate drainage is crucial to preventing track damage. Additionally, the installation of prefabricated vertical drains re­sults in increased subgrade soil stabilisation.

Airports: 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.

Geosynthetics are critical for resolving 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. Additi­o­nally, as aircraft manufacturing and design technology progresses, longer and stronger run­ways must be constructed to accommodate the diverse forms and weights of aircraft. Geo­synthetics tackle these concerns while also offering more environmentally friendly design options and requiring less long-term upkeep.

To provide a smooth and equal surface on runways and for strengthening pavements, substantial use of geosynthetics is required. To create the flat surface required for runways and other airport infrastructure, steep reinforced em­­bankments or gabion barriers are used.

Ports: Indian coastal areas have unique geomechanical features such as soil instability and soft soils leading to a weak foundation. States requiring significant amount of investments in geosynthetics such as gabions and geobags are Odisha, Tamil Nadu, Maharashtra, Kerala and Andhra Pradesh. Non-woven geotextiles and geogrids are widely used for soil stabilisation in the rapidly increasing Indian ports. These are placed below the subgrade to improve the California Bearing Ratio and load bearing capacity of the soil, enabling it to handle high axle load.

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. According to India In­fra­structure Research, 704 tunnels totalling 2,847 km will be constructed in the coming years, resulting in a major increase in the demand for geosynthetics. These materials are widely uti­li­sed in tunnel sealing systems because they inhibit corrosion and inc­rease structural str­en­g­th. Additionally, tunnel lining uses non-woven geotextiles and geo­mem­branes, which allow for effective water drainage into the side ditches.

Irrigation: The geosynthetics business has produced a number of materials over the past few decades that are valuable for developing irrigation and drainage projects, particularly for re­du­cing seepage and erosion. At present, 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. Now­­adays, geosynthetic materials are available that satisfy project criteria and have a durability comparable to the project’s design life, ensuring the project’s lifespan.

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. These materials 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.

Going forward

By end-2022, the government intends to en­hance the manufacturing sector’s contribution to GDP from 16 per cent to 25 per cent. This will increase the demand for geosynthetics us­ed in a variety of industrial building applicatio­ns. In general, the geosynthetics market in In­dia is predicted to grow significantly over the forecast period 2022-25.

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