A Composite Gabion Fascia?Reinforced Soil Wall for Navi Mumbai International Airport
Completed Gabion Fascia Reinforced Soil Wall
The proposed plan of River training work at Gadhi River, New Mumbai International Airport
As India has grown in population and economic influence, the country’s airport infrastructure has been strained. The existing Mumbai Airport, in particular, has been in need of greater support to handle the passenger and cargo traffic. For decades, a new airport was discussed. Finally, a proposal led by City and Industrial Development Corporation (CIDCO) put in motion the construction of Navi Mumbai International Airport.
The Greenfield site, located on the banks of Gadhi River near Panvel Creek, is still under construction. Roughly 1600 hectares of land are being reclaimed in this river basin zone and the river itself is being trained along the airport premises to retain backfill soil material on the upstream side. The strategy will help protect the airport from flooding during heavy monsoons and drawdown during the dry season.
Siting the airport along this waterway is not an easy endeavor. Gadhi River is the main river of the Panvel creek and has a hard rock bedding surface. The adjacent development of industrial and residential land in Panvel City forces stormwater from Thane creek into the Gadhi River, causing water level surges.
In July 2005, the river had an HFL (high flood level) of 6.5 m. Thus, a safe-grade elevation of 9m from bedrock level was proposed for Navi Mumbai International Airport, to achieve this level, a retaining wall was needed to train the river along the Panvel creek.
Photographs of Catchment area of Gadhi River with Inundated rock formations.
REINFORCED SOIL WALL – COMPOSITE SYSTEM
Based upon the site conditions and project needs, the engineering team opted for a reinforced soil wall that would provide a sustainable, environment-friendly face to the perimeter infrastructure. The composite design used a reinforced soil wall with metal gabions as fascia—an extremely effective approach for land reclamation and river training projects.
A high-strength polyester uniaxial geogrid (Tech Grid (TGU) from TechFab India) was selected as the reinforcing element. TechFab Metal Gabion was chosen for the fascia. TechFab Metal Gabion featured GI wire mesh with a special coating of zinc90%+Al10%+ PVC coating to ensure the facing was durable against the annual fluctuations in sun and rain exposure. The system also ensured strong protection against erosion to protect the backfill material.
The reinforced soil wall was designed using BS 8006 design standards. The metal gabion mattresses were installed with a height of 2.5m from the hard rock level to prevent inundation and sliding at the toe of the retaining wall. The maximum height of the reinforced soil wall was 11.5 m.
The geogrids were installed with the stone-filled metal gabions along with 12mm connector rods. U-pins were used to fix the Geogrid in the reinforcing zone.
The porosity of the metal gabion system allowed the dissipation of pore water pressure from the backfill material as and when required. TechGeo Nonwoven Geotextile was installed as filter media to allow water to drain through while retaining the soil particles.
Typical Cross-section of Metal Gabion Fascia Reinforced soil wall
Arrangement of Metal Gabion Mesh with connector rod
Installation, Filling of Gabion mesh with stone fillings in progress
Installation of geogrid and laying of infill material in progress
Completed Gabion Fascia Reinforced Soil Wall
Advantages of Using Metal Gabion Fascia Reinforced Soil Wall
The composite system of the metal gabion fascia and reinforced soil wall produced a number of benefits for the Navi Mumbai International
Airport construction:
- The composite system did not require the heavier or deeper foundation that a conventional retaining wall would have
- The permeable nature of the system guarded against hydrostatic pressure build-up and uplifts from turbulent flow
- The flexible fascia enables the system to withstand some differential settlement without fracturing the structure, particularly when a structure is installed on unstable and uneven ground or in areas in which waterway conditions would otherwise threaten to scour
- Vegetation was permitted to grow with the system, thus enabling it to blend into the natural environment
- The structure was more cost-efficient and faster and easier to construct compared to other rigid similar function structures (e.g., conventional concrete walls)
Author
Namrata Bichewar (Design Engineer)
TechFab (India) Industries Ltd.
Manish Barot
Head of Technical Sales and
Business Development,
TechFab (India) Industries Ltd
Current Issue
12-2025
