Gabion retaining walls provide stability by their mass, resisting the disturbing forces. They are considered to be a flexible and free draining retaning wall system. The design procedures for this walling follows the design criteria of BS8002 – ‘The Code of Conduct for Earth Retaining Structures.
When designing the retaining wall, checks must be carried out at each course level to ensure that the stability criteria is achieved throughout the whole of the structure. It is normal to incline the walls from the vertical by 6 or 10 degrees for aesthetic and stability reasons.
The degree of inclination is a maximum of 6 degrees for the Gabion 39 System and 10 degrees for the Gabion 27 System (which is the preferred product type for these structures). The walls can either be stepped or flushed face.
The degree of flexibility of a retaining wall system is dependant upon the type of fill, quality of filling, mesh type and wire diameter of the mesh.
Typically, the more angular the fill, the greater care in filling and the heavier the wire diameter of the mesh - the higher the quality of installation. This results in a more dimensionally stable structure.
For mass gravity gabion retaining walls along water courses where flexibility is required, the preferable gabion type is one manufactured from double twist woven hexagonal mesh.