Historically, gabions (from Italian gabbione meaning “big cage”; from Italian gabbia and Latin cavea meaning “cage”) were round cages with open tops and bottoms, made from wickerwork and filled with earth for use as military fortifications. Modern definitions include any caged rip rap for erosion control, or cylindrical metal structures used to build dams or foundations.
The most common civil engineering use is to stabilize shore against erosion. Other uses include retaining walls, temporary flood walls, to filter silt from runoff, and for small or temporary dams. They may be used to direct the force of a flow of flood water around a vulnerable structure. Gabions are also used as fish barriers on small streams.
Gabion baskets have some advantages over loose rip rap because of their modularity and ability to be stacked in various shapes. They also have advantages over more rigid structures because they can conform to ground movement, dissipate energy from flowing water and 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 keep stones which may fall from a cutting or cliff from endangering traffic on a thoroughfare.