Gabions and geotextiles work together
Where there are soft soil conditions, geotextiles are an essential component of gabion installations; but with clay, the opposite is true. Then there’s the geotextile overlap. By Alastair Currie
Gabion walls constructed as freestanding structures are intended to serve as architectural features and not retaining systems. However, these walls still need a central steel support system and must be founded on concrete.
“It illustrates the fact that gabions have a very diverse range of architectural and construction applications, and that each installation needs to be specifically designed and built to serve its intended purpose,” says Louis Cheyne, managing director of Gabion Baskets.
If built well, gabion installations will last for decades. A more recent example that ticks all the right boxes is an approximately 80 m long contoured gabion retaining wall commissioned by the City of Cape Town. What makes this installation distinctive is that tubular gabions were installed, which require an extra level of proficiency from both the designer and contractor. This installation was erected in Cape Town’s northern suburb of Tygerberg. The 4 m high retaining wall is founded on a gabion mattress foundation.
The wall runs alongside a river channel section that borders a multistorey building on the one side and a paved road on the other. The primary purpose of the wall is to protect the building’s exposed pile foundations against erosion, while ensuring embankment stabilisation in case of flood events. Says Cheyne, “The tubular gabion effect has a strong aesthetic appeal since it reduces visible joins, which can sometimes look untidy, depending on the proficiency of the