Non-Woven Geotextile at Leh Airport: Ocean Non Wovens Case Study

For HRY Kundu Builtech, Ocean Non Wovens supplied and installed 2,400 sq m of Non Woven Geotextile 200 GSM at Leh Airport, where it was used for subgrade stabilisation and drainage beneath runway and taxiway pavement. Ocean also supplied 1,060 Ocean Gabion Boxes to the same project. Leh sits in a high-altitude cold desert in Ladakh: winters are far below freezing, the air is thin, and every truckload of material comes over long mountain roads. A pavement here has to cope with frost and heavy aircraft loads, and repairs are hard to schedule.

Geotextiles in airport pavements

Runways and taxiways carry repeated heavy aircraft loads and must not settle unevenly. In airfield pavements, geosynthetics are used mainly for separation, filtration, drainage and reinforcement. A non-woven geotextile placed on the subgrade keeps the granular base clean and lets water drain out of it, so the base keeps its strength and thickness under traffic.

Challenges of the Leh region

• Frost action: the ground freezes seasonally. Water in fine soil expands as it freezes, lifting the surface, and the soil softens when it thaws, which leads to cracking and loss of support.
• Short construction window: snowfall and sub-zero temperatures limit outdoor work to a few months a year.
• Remote access: materials travel long distances over high mountain passes, so deliveries need careful planning.

For these conditions, Ocean recommended its 200 GSM Non Woven Geotextile for its mechanical strength, permeability and tolerance of cold.

Why 200 GSM non woven geotextile

Ocean Non Wovens’ 200 GSM Non Woven Geotextile is made from polypropylene fibres, needle-punched into a thick, porous fabric. It does four jobs here:

1. Separation and stabilisation: it stops the subgrade and aggregate layers intermixing, so the base keeps its load-spreading thickness.
2. Drainage: water passes through while fines are held back. A drier base and subgrade hold less water that can freeze, which limits frost damage.
3. Cold tolerance: the fabric stays flexible and stable in service at low temperatures once it is buried.
4. Durability: polypropylene resists biological and chemical degradation in soil, so the buried layer keeps working long term [1].

Ocean Gabion Boxes at the airport

Alongside the geotextile, Ocean supplied 1,060 Ocean Gabion Boxes. A gabion box is a wire mesh cage filled on site with stone and laced to its neighbours, so the units act together as one heavy, flexible structure. On airfield works, gabions are typically used for retaining walls at cuttings and embankment edges, for lining and protecting drainage channels and outfalls, and for erosion protection on slopes where snowmelt and runoff concentrate.

Two properties suit them to a site like Leh. The stone fill is free-draining, so meltwater passes through the wall instead of building up pressure behind it. And the mesh tolerates movement: a gabion wall can deform slightly with frost heave or settlement where a rigid concrete wall would crack. A non woven geotextile is normally placed between the retained soil and the back of the gabions as a filter, so fines do not wash into the stone.

Execution and installation

Installation needed close coordination because of limited daylight working hours and the time crews needed to acclimatise. Ocean’s engineering team worked with the on-site contractors so the geotextile was laid uniformly with proper overlaps, anchoring and protective cover. Each section was inspected for wrinkles and gaps, since these leave soil and aggregate in contact and become weak spots over time.

Site practices specific to working at altitude included:

• Acclimatisation protocols: the field team followed a mandatory acclimatisation routine for Leh’s elevation of around 3,500 metres before starting physical work.
• Material handling: polypropylene stiffens and becomes more brittle in sub-zero temperatures, so rolls were kept in insulated shelters until they were laid.
• Environmental care: packaging was eco-friendly and waste was disposed of according to the applicable guidelines.

Ocean Non Wovens manufactures and supplies geosynthetics for airfields, roads and infrastructure projects across India, from remote sites in Ladakh to large urban works. For another airfield job, see the runway upgrade at Bangalore Airport, or browse more case studies.

Reference:
[1] Koerner, R. M. (2012). Designing with Geosynthetics, 6th Edition