Geotextiles: Functions and Usage

Geotextile functions

When used in geotechnical and civil applications, the geotextile will fulfill one or more functions in that design.


The geotextile will act as a physical barrier to separate 2 layers of different soil or fill material. This will help to maintain the integrity of the different layers of the design and increase the long-term stability of the construction.
In road construction it will prevent the movement of road base material into the soft subsoil layers. In railways it will prevent the upward migration of fine soil particles into the ballast (pumping effect).


Used as a filtration layer, the geotextile allows fluids to move through the soil and the filter layer, while preventing the soil particles from moving.
A geotextile will for example be used as a wrap-around in a drainage trench, allowing the water to flow into the drainage trench but making sure particles can not contaminate the drainage aggregate.


A geotextile can act as a protective layer against mechanical damage during installation and after completion of a construction project.
In e.g. tunnels or landfills, waterproofing membranes can be protected from punctures by stones in the soil or waste by adding a geotextile as a cushioning layer.


The geotextiles act as a conduit to carry liquids, in the plane of the geotextile, through less permeable soil layers. Often, relatively thick nonwovens are used to provide drainage capacity.
In road embankments, geotextiles can be used to spread water pressure that may come up at the base of the embankment.


The geotextile will form a reinforcement element in the construction through interaction with the soil in order to better resist tensile forces put on the construction.
Geotextile reinforcement will for example allow the construction of embankments over very soft foundations or the creation of steeper slopes.

Erosion control

In erosion control, the geotextile prevents or reduces erosion from wind, surface water, and rainfall by protecting the soil surface.
In coastal erosion control systems with rock armour, heavy-duty geotextiles can be used underneath the rocks to prevent erosion of the base soil layer.

Stress relief

Geotextile provides stress relief in asphalt overlays and will reduce reflection, fatigue, and temperature cracking by delaying and arresting crack propagation.
It can be installed as an interlayer in asphalt pavement layers of new or resurfaced roads and as such increase the lifetime of the pavement.

Interlayer barrier

Between 2 asphalt layers, a geotextile can act as an interlayer barrier to prevent the ingress of water and oxygen into bound and unbound layers of the road construction.
When the geotextile, in a road structure, is saturated with bond coat it will form a barrier, thus delaying deterioration and prolonging the bearing capacity of the structure.