Gabion Application 1 - Retaining walls
Gabion walls can be built with speed and economy in all circumstances and are particularly suitable for landslide control in mountainous countries and in areas with persistently bad ground conditions. Where ground is liable to subside, the capacity of gabions to deform makes them preferable to a concrete wall which would crack and collapse.
Gabion gravity retaining walls are typically placed directly on a graded soil foundation. The base width of a gabion gravity retaining wall is directly related to the height of the wall. As the wall height increases, the base of the wall must become wider to ensure structural stability. We have provided the diagrams below to illustrate a starting point for design analysis to determine the base width relative to the wall height. A conservative rule-of thumb value of base width = 2/3 wall height.
Geo-textile filter fabric is a vital component of any gabion retaining wall project. The rock voids within the gabion baskets allows for free drainage of the retained soils and requires a filter fabric be placed between the gabion wall and the backfill soil interface. The geotextile filter fabric will minimize hydrostatic pressure and prevent loss of soil during drainage and drawdown. Gabion gravity retaining walls constructed without the placement of filter fabric will have a tendency to incur a loss of retained soils and grade elevation behind the gabion wall. The type of backfill soil specified will determine the type, and placement of the geotextile filter fabric.
To provide the maximum resistance to soil forces the gabion baskets should be placed with the length dimension of the gabion unit running from the back of the gabion wall to the front face of the gabion wall. This will result in the internal diaphragms being placed perpendicular to the wall face and parallel to soil thrust. When gabion units are placed with the length dimension of the gabion unit running parallel with the length dimension of the wall the vertical seams shall be offset.
Gabion retaining walls can be designed and configured with a stepped front face or a smooth front face. When utilizing a gabion wall with a smooth front face, the gabion wall should be placed on a 5-6 degree batter and is not recommended for walls above 18’ high. Gabion walls with a stepped front face shall have a minimum 1’-1.5’ horizontal set back for each 3’ vertical lift.
Gabion gravity retaining walls can be designed and constructed up to approximately 30’, however due to the configuration of gabion gravity retaining walls their best suited for wall heights of 18’ or less. For wall heights of 18’- 36’ consider two separate walls divided by a level plateau or see the Stable Slope Section of this web site.
Note: All the above are for information only and not to be considered design recommendations.
Hangxuan, Wire Mesh Gabion Manufacturing Specialist.