What Is Geogrid? Functions and Geogrid Types

Geogrid is a material classified as a geosynthetics product. It comes in sheets with frame-like apertures and functions as reinforcement to strengthen soil-reinforcement structures. Geogrid types vary in aperture shape, which is generally square, oval or another form.

Geogrid works by being placed on the ground surface and then covered with fill. Interlocking occurs as the fill enters the apertures between the geogrid ribs, producing high frictional resistance.

Understanding Geogrid Types

Three geogrid types are commonly available and widely used in construction projects. They are distinguished by the shape of their apertures.

Biaxial Geogrid

Biaxial geogrid has characteristic square apertures. This type functions as a subgrade stabilization material that helps prevent differential settlement and reduce maintenance costs. Biaxial geogrid can also reduce base or subbase thickness by up to 60%, lowering construction costs.

Triaxial Geogrid

This type is called triaxial because it has triangular apertures. Its function is nearly the same as the biaxial type: reinforcing soil on slopes and beneath roads, where it can be combined with woven geotextile.

Uniaxial Geogrid

This geogrid type has slightly wider apertures than the 2 preceding types. Its function is also nearly the same as other geogrids, but it is more commonly applied to slope stabilization, allowing taller structures to be built in relatively confined spaces.

Geogrid Functions

This material has 2 main functions: reinforcement and base-course stabilization. These functions differ in how they perform, as explained below:

As Reinforcement

Geogrid tensile strength plays a major role in reinforcement. Geogrid can reinforce structures such as embankments, soft soil and steep slopes. When it is used to reinforce an embankment over soft soil, however, an additional material is needed: non-woven geotextile, which serves as a separator.

As a Stabilizer

When geogrid is used as a stabilizer, the geogrid and aggregate work together to form a composite mass with a higher modulus and greater stiffness than aggregate without a stabilizer. Stabilization requires stiffness at low strain but does not require high ultimate tensile strength.