Gabions are wire, stone filled cages or mattresses and are normally used to retain or protect slopes for erosion e.g. along river banks. Single skin gabion walls can be further improved by reinforcing the soil behind the wall to form a combined / reinforced soil structure. The gabion cages are usually manufacture with PVC coated hot dipped galvanised wire. The gabion cages are normally assembled in modular form with the cages available in lengths up to say 6 metres by 2 metres wide by up to 1 metre deep, which are subdivided into compartments with internal walls or baffles to provide strength for the structure. The stone fill for the gabions should be placed in the compartments by hand or machinery starting at the bottom if on a slope and working up if on say a 6 metre length, filling compartment by compartment to form the gabion structure. Fill used for gabions should be hard durable stone and not less than 75mm, and not less than 150mm for gabions in rivers or for marine works. The gabions should be slightly overfilled to allow for settlement and the lid fitted securely to the gabion baskets. For non standard shapes the gabion mattresses can be cut to size

Gabion mattresses are box units where the plan area is large compared to its height. Each unit is subdivided into compartments normally to give cells 2mx1m in plan.

Typically standard sizes are 3mx2mx0.3m and supplied in a Zinc or PVC/Zinc coated wire.
The units are laid on the bed of rivers. Once filled with stone or rock and the lid closed, they form a blanket erosion control system.
Gabion Mattresses are also used to provide underscour protection to retaining structures.

Weldmesh mattresses are large in plan compared to their height and supplied in multiples of the mesh aperture typically up to 300mm high. They are subdivided with internal diaphragms placed at 1m intervals to give maximum internal compartment sizes of 2m x 1m.
Where water flow is high, additional internal diaphragms maybe placed to reduce the compartment sizes and prevent movement or migration of stone. The correct grade of stone is essential as well as packing of the compartments to reduce the potential for movement.

Mattresses are manufactured from lighter grades of wire for their flexibility. Applications include scour protection beneath gabion walls where erosion in watercourses is prevalent and as channel lining to storm water drains and culverts.

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