Gabions baskets are made of hexagonal woven wire mesh. They are filled with rock at the project site to form flexible, permeable and monolithic structures such as retaining walls, channels and weirs for erosion control projects.
River Bank Protection
The wire is heavily zinc coated and for added protection can also be PVC coated. Stainless steel wire is also available on special order. The gabions boxes are supplied in various sizes, 2 m long by 1 m wide by 1 m high being the most popular size. The diameter of the wire used can also be varied within
limits.
Coastal Erosion
PVC coated gabions will normally be specified in applications requiring additional protection against corrosion for example in the tidal zone of rivers, or when additional wear and tear protection is required against boulders transported by flood waters. It is important to be aware that transported cobbles and boulders can cause severe damage to the mesh and its coatings, reducing the life of the gabion considerably. For more severe exposure to sea water, stainless steel wire should be considered.
The rock to be used for filling the gabion boxes and mattresses are normally obtained from sources on or near the site and should be durable and of sound quality ranging in size between 100 mm and 250 mm for boxes and between 75 mm and 150 mm for mattresses. A well packed gabion can have a very neat appearance.
Benefits of Gabion in River and Coastal Erosion Control:
- Rapid Construction with immediate use.
- Disipate flowing water energy.
- Semiflexible building blocks for channel stabilisation.
- Have an irregular surface to diffuse and reduce river bank scouring.
- Gabions use of smaller rock for river bank protection. When large rip rap is unavailable.
- Much cheaper, more flexible and greener than concrete.
- Can be installed in dry or wet conditions.