Specifications for a Gabion Retaining Wall

Gabion Retaining Walls

• Construct gabion retaining walls by arranging galvanized wire baskets, called gabions, in position and filling them with stones. They're a gravity-type wall, depending on weight to resist lateral and hydraulic pressures from the soil being retained and water build-up in the soil. Gabion walls are a hard landscape structure. They are used on steeper slopes than rip rap and for erosion control where there isn't room for vegetation.

Wire Baskets

• The rectangular wire baskets are fabricated into a nonraveling hexagonal mesh made from hot-dipped, galvanized steel wire. For handling and shipping, the baskets are folded flat and bundled. They're unfolded for assembly and all vertical edges are bound together with lengths of wire. The empty baskets are set into place and adjoining baskets are wired together. The wire gauge for the baskets depends on the wall’s height the pressures bearing on it.

Stone Fill

• Stones for the baskets are usually specified as 3- to 8-inch hard, clean stone. The stone’s interlocking action keeps the baskets’ internal structure stable. The stones are placed in the baskets in 12-inch lifts or layers with equipment, and then finished by hand for even distribution and aesthetics. After one-third of the basket is filled, connecting wires are installed both ways tying the basket walls together keeping it from bulging.

Installation

• Gabion walls are stepped back in terraces or angled back into the slope. The foundation depends on the wall’s size and height. Generally, the base has to be well-compacted, granular material with suitable load-bearing strength. Each basket course is filled and wired, and the lids closed and bound shut before beginning the next one. The baskets for each layer are staggered to offset the vertical joints, and the empty baskets are wired to the filled ones before filling with stones.