Case Study: Reinforcing Railway Infrastructure in Hotgi, Maharashtra with Ocean Biaxial Geogrid-30kN (80,000 SQM)

Ocean Non Wovens supplied 80,000 SQM of Ocean Biaxial Geogrid-30kN to reinforce the track formation of a heavy freight railway corridor at Hotgi, Maharashtra, near Solapur. The stretch had suffered track misalignment and recurring maintenance because of soft subgrade, especially during the monsoon. The geogrid was placed beneath the ballast and sub-ballast to confine the granular layers and spread train loads more evenly onto the subgrade.

Why the track bed needs reinforcement

India’s railway network covers over 68,000 route kilometres and carried about 6.9 billion passengers and around 1,588 million tonnes of revenue freight in 2023–24 (Economic Survey of India). Heavier axle loads and denser schedules put more stress on the track substructure. Where the subgrade is weak or poorly drained, the track bed settles unevenly, ballast spreads, and the line needs frequent tamping and ballast top-up.

The traditional answer is thicker granular layers. On soft ground that means more excavation, more imported stone and more time. Biaxial geogrids, one of the reinforcement geosynthetics now common in formation work, improve the granular layer instead:

• Load distribution: they spread vertical loads over a wider area, lowering stress on the subgrade.
• Lateral confinement: aggregate interlocks with the grid apertures, so particles cannot spread sideways under repeated loading.
• Reduced settlement: less long-term deformation and less differential settlement along the track.
• Lower construction cost: the design can often use a thinner sub-base or marginal fill.

The Hotgi railway project

Project Overview: rehabilitation and reinforcement of a heavy freight railway corridor at Hotgi, Maharashtra, prone to track misalignment and recurring maintenance because of soft subgrade, especially in the monsoon.

Challenge:

• Weak, clayey subgrade with low California Bearing Ratio (CBR) values
• Frequent ballast loss and uneven settlement
• Need for rapid installation without disrupting ongoing traffic

Product Deployed: 80,000 SQM of Ocean Biaxial Geogrid-30kN, selected for its tensile strength in both directions, aperture geometry, and resistance to UV and installation damage.

Technical properties of Ocean Biaxial Geogrid-30kN

Execution and installation

Ocean’s technical team worked with the project engineers on delivery and deployment. The process:

1. Subgrade preparation: the ground was levelled and compacted.
2. Geogrid placement: rolls were laid with 300 mm overlaps and fastened with polymeric pegs at regular intervals.
3. Ballast placement: sub-ballast and ballast were placed over the geogrid without disturbing its alignment.
4. Vibratory compaction: the layers were compacted mechanically to seat the aggregate into the grid apertures.
5. Inspection: post-installation QA/QC included pullout and field plate load tests.

What the geogrid does for the track

The geogrid addresses the ground stability problems that caused the recurring maintenance. In a reinforced formation of this kind:

• Settlement is reduced because the confined granular layer spreads load and deforms less under repeated axle loads.
• Track geometry holds longer because ballast cannot spread sideways as easily, so tamping and line blocks are needed less often.
• Construction is quicker where reinforcement lets the design reduce excavation and fill depth.
• Ballast lasts longer because less particle movement means less abrasion and breakdown, which is one source of ballast fouling.
• Less natural aggregate and excavation are needed, which lowers the project’s material and transport footprint.

The Hotgi stretch is prone to seasonal waterlogging. Polypropylene does not absorb water or rot, so the grid’s strength is not lost when the formation is saturated. Drainage still matters, though: a geogrid confines aggregate but does not stop fines pumping up from a wet clay subgrade. Where that is a risk, a non woven geotextile separator or a blanket layer is normally provided as well.

About Ocean Non Wovens

Ocean Biaxial Geogrid-30kN is made from polypropylene under ISO-certified processes and tested for tensile strength, durability and environmental resistance. Ocean Non Wovens supplies geogrids and other geosynthetics for passenger and freight rail projects, with on-site technical support.

Planning a rail infrastructure upgrade or dealing with ground stabilisation problems? Contact Ocean Non Wovens or explore our geogrid range at www.oceangeosynthetics.com. More rail and infrastructure work is on our case studies page.

Frequently asked questions

What is the purpose of biaxial geogrids in railway construction?

They reinforce the granular layers of the track formation. The grid confines the aggregate, spreads train loads more evenly onto the subgrade and reduces settlement, which matters most on weak or moisture-sensitive soils.

How does Ocean Biaxial Geogrid-30kN improve track stability?

It has a tensile strength of 30 kN/m in both directions. Aggregate interlocks with its apertures, which limits ballast movement, controls differential settlement and helps the track hold its geometry, so it needs less maintenance.

Is geogrid installation disruptive to railway operations?

Geogrid rolls are light and quick to lay, and reinforcement can reduce the excavation and fill depth needed, which shortens the work. How much disruption a job causes depends on the line block arrangements for the site.

Do biaxial geogrids work in waterlogged or monsoon-prone areas?

Yes. Ocean Biaxial Geogrid-30kN is polypropylene, which does not absorb water and resists UV and chemical degradation, so it keeps its strength when saturated. Good drainage and, where needed, a geotextile separator are still required on wet clay subgrades.

How do I choose the right geogrid for my project?

It depends on soil type, subgrade strength, expected loads, traffic frequency and the design life. Ocean Non Wovens offers free technical consultations and site-specific design support to help select the right grade.