1. Gabions must be installed on a surface prepared to the levels and quality of the engineers specifications for the project.
2. Rockfill for the gabions must be quarried rock of sizes and quality in accordance with the engineering specifications for the project.
3. Before filling, gabions should be placed on the prepared surface and tensioned to ensure that the shape is good and that exposed surfaces are smooth and taut. A suitable tensioning arrangement is shown in the following picture.
4. Filling of gabions with rockfill may be by machine or hand taking care to minimise voids. However, exposed faces must be filled by hand using selected larger pieces of rock with flat faces to give a fair face to the rockfill inside the exposed geogrid face.
5. If the gabion height (H) is more than 500mm then cross-ties of HDPE braid should be installed at vertical intervals of 250-400mm to improve stability and quality of finish.
6. Slightly over-fill each gabion, using smaller stones on the surface, to allow for settlement. Encourage settlement, for example by walking on the rockfill.
7. Adjust finished surface of rockfill as needed.
8. Close down top of gabion and tightly lace, all edges and top-diaphragm joints.