A
gabion is a cage, cylinder, or box filled with rocks, concrete, or sometimes sand and soil for use in civil engineering, road building, military applications and landscaping.
For erosion control, caged riprap is used. For dams or in foundation construction, cylindrical metal structures are used. In a military context, earth- or sand-filled gabions are used to protect sappers, infantry, and artillerymen from enemy fire.
Civil engineering
A gabion wall is a retaining wall made of stacked stone-filled gabions tied together with wire. Gabion walls are usually battered (angled back towards the slope), or stepped back with the slope, rather than stacked vertically.
Gabion baskets have some advantages over loose riprap because of their modularity and ability to be stacked in various shapes. Gabions have advantages over more rigid structures, because they can conform to subsidence, dissipate energy from flowing water and resist being washed away, and they drain freely. Their strength and effectiveness may increase with time in some cases, as silt and vegetation fill the interstitial voids and reinforce the structure. They are sometimes used to prevent falling stones from a cut or cliff endangering traffic on a thoroughfare.
Gabions have also been used in building, as in the Dominus Winery in the Napa Valley, California by architects Herzog & de Meuron, constructed between 1995 and 1997. The exterior is formed by modular wire mesh gabions containing locally quarried stone; this construction allows air movement through the building and creates an environment of moderate temperatures inside.
Variations in design
There are various special designs of gabions to meet particular functional requirements and some special terms for particular forms have come into use. For example:
Bastion: a gabion lined internally with a membrane, typically of nonwoven geotextile to permit use of a granular soil fill, instead of rock.
Mattress: a form of gabion with relatively small height relative to the lateral dimensions; commonly very wide. For protecting surfaces from wave erosion and similar attack, rather than building or supporting high structures.
Trapion: a form of gabion with a trapezoidal cross section, designed for stacking to give a face that is sloping rather than stepped. The term is in wide usage, but in contexts related to gabions at least, appears to be a trademark registered by Betafence Limited.
Military use
Early gabions were round cages with open tops and bottoms, made from wickerwork and filled with earth for use as military fortifications. These early military gabions were most often used to protect sappers and siege artillery gunners. The wickerwork cylinders were light and could be carried relatively conveniently in the ammunitiontrain, particularly if they were made in several diameters to fit one inside another. At the site of use in the field, they could be stood on end, staked in position, and filled with soil to form an effective wall around the gun, or rapidly construct a bulletproof parapet along a sap. Today, gabions are often used to protect forward operating bases (FOBs) against explosive, fragmentary, indirect fires such as mortar or artillery fire. Examples of areas within a FOB that make extensive use of gabions are sleeping quarters, mess halls, or any place where there would be a large concentration of unprotected soldiers.
