Application of Ocean Geogrids in Railways

Ocean Geosynthetics makes geosynthetics for the Railways and has more than 20 years of experience in the geosynthetic industry, supplying materials for ground improvement, base stabilisation, track drainage and track bed stabilisation. Ocean Geogrids are used in railway track for ballast and sub-ballast stabilisation.

The Significance of Geosynthetics in Railways:

In railways, high-speed corridors and heavier axle loads need stable, stiff track beds. The main problems are settlement, weak subgrade soils, poor load distribution, and loss of track geometry as the ballast degrades and spreads.

Geosynthetics address these in several ways. In the railway sector, geosynthetics products and materials are used for soft subgrade stabilisation, ballast reinforcement, separation and filtration between ballast and subgrade, improving the stability of the sub-ballast and capping layers, and reinforcing rail embankments. Reinforcing a layer can also reduce the thickness of quarried aggregate needed, which lowers both cost and the carbon footprint of construction.

Role of Geogrids in Railways:

Track is a harsh environment for a geosynthetic: angular ballast abrades and punctures, and every passing train applies a repeated high load. Ocean geogrids are made to withstand both.

Geogrids are reinforcing geosynthetics made from polymers such as polyester, high-density polyethylene and polypropylene. Intersecting ribs, running in the machine and cross-machine directions, form the grid, and the openings between them are called apertures.

Depending on the direction in which the ribs are stretched during manufacture, geogrids are uniaxial or biaxial. Uniaxial geogrids have high tensile strength in the longitudinal direction only, while biaxial geogrids have similar tensile strength in the longitudinal and transverse directions, which suits track beds where load spreads in all directions.

For where the grid is placed in an Indian Railways formation, our guide to geogrid in railway construction covers the blanket, the subgrade surface and the ballast, and what a geogrid will not fix.

Ballast and subballast stabilization with Geogrids:

When ballast or sub-ballast is placed on a geogrid, the particles penetrate the apertures and lock against the ribs. That interlock restricts particle movement, which improves the load-bearing capacity of the unbound aggregate and spreads the load over a wider area of the subgrade. For this to work, the aperture size must suit the particle size of the ballast or sub-ballast it is placed in.

Confining the granular layer also reduces lateral spreading of the ballast, so the track bed holds its shape for longer.

Ocean Geogrids in track beds are intended to:

• Lower construction costs
• Speed up construction and installation
• Maintain track geometry and alignment
• Reduce ballast settlement and traffic-induced degradation
• Reduce maintenance costs by extending maintenance intervals

For an example, see Ocean’s case study on reinforcing railway infrastructure in Hotgi, Maharashtra with Ocean Biaxial Geogrid-30kN.

Ocean Geosynthetics’ engineers can advise on choosing a geogrid grade to suit your railway project specification.

Need more information? Please contact us.