Case Study: Enhancing Railway Infrastructure in Gadchiroli, Maharashtra with Ocean Geocomposite 700 GSM

Project overview

For a railway infrastructure project in Gadchiroli, Maharashtra, Ocean Non Wovens supplied and installed 10,000 square meters of Ocean Geocomposite 700 GSM to deal with the site’s soft, wet subgrade.

Gadchiroli is a heavily forested district in eastern Maharashtra with high monsoon rainfall, and new railway lines there are being built to improve connectivity. Building track formation on this kind of ground raises three problems that geosynthetics address: separating ballast and blanket from a weak subgrade, draining water out of the formation, and holding up under repeated train loads.

Why a geocomposite in railway formation

Railway track carries heavy, cyclic axle loads in all weathers. If the formation beneath it is weak or wet, the track settles unevenly and needs frequent re-packing, and in bad cases speed restrictions follow.

Ocean Geocomposite 700 GSM is a non-woven geotextile thermally bonded to a geonet core. The geotextile filters and separates; the geonet provides an open path for water to flow along the plane of the sheet. The result is a single layer that separates and drains at the same time.

Site challenges and how the geocomposite addressed them

Soft soil and low bearing capacity

Gadchiroli’s soil had low shear strength and held a lot of water. Conventional practice would have meant excavating and replacing large volumes of unsuitable soil, adding time and cost.

Placed between the subgrade and the overlying granular layers, Ocean Geocomposite 700 GSM kept the two from mixing. Under cyclic loading, a soft wet subgrade otherwise pumps fines up into the blanket and ballast while stone punches down into the soil, and the formation loses strength. Keeping the layers separate and the subgrade drained preserves the strength of the granular layer, which reduced the amount of earth that had to be replaced.

Drainage

Water trapped in the formation softens the subgrade, causes erosion and leads to mud pumping under traffic.

The geonet core carries water laterally out of the formation to side drains, so it does not build up beneath the track bed. Draining the formation reduces maintenance and extends the time between track repairs.

Durability under cyclic loads

Track formation is loaded and unloaded with every passing axle. The geocomposite has to keep its filtration and flow capacity under that load without its geotextile clogging or its core crushing. Polymer geocomposites do not rot or corrode in wet ground. In India, RDSO publishes guidelines and specifications for the use of geosynthetics in railway formation.

What Ocean Non Wovens provided

Ocean Non Wovens supplied the material and also provided on-ground support, technical consultation and quality control during installation. The aims were:

• Better track performance: a stiffer, better-drained formation reduces the risk of track deformation and settlement.
• Less excavation and haulage: using a geocomposite instead of replacing soil cut down earthmoving and material transport, and with it the project’s emissions.
• Lower lifecycle cost: a formation that stays drained needs fewer repairs.

Poor subgrade and inadequate drainage are well-known causes of track-geometry problems on Indian railways, which is why formation treatment is now part of the design on difficult ground.

Support after installation

Ocean Non Wovens also provided:

• Training for on-site teams
• Post-installation inspection
• Documentation and traceability of product use
• Environmental compliance reporting

About Ocean Geosynthetics

The Gadchiroli project used 10,000 Sqm of Ocean Geocomposite 700 GSM to separate and drain a soft railway formation. Ocean Geosynthetics supplies geosynthetics for railway, road and hydraulic projects across India. See the geonet range or more case studies.