Gabion wall on a cut slope
Geotechnical
- Ground
- Cut slope, weathered near surface
- Method
- Slope stability assessment
- Scope
- Gravity retaining, free draining
- Outcome
- Wall sized to the assessed loads
Not every retaining wall wants to be concrete. Where the cut is modest, drainage matters and the finish is going to be looked at, a gravity structure built from rock-filled baskets does the job and lets the water through instead of holding it back.
A gravity wall only works if the ground behind it is stable enough to be held by mass rather than pinned back, so that question was settled before any wall was sized. The wall was then set against the loads the assessment produced, stepped into the cut and founded below the weathered zone.
Free draining construction means no water pressure builds behind the face, which is the failure that takes out more small retaining walls than any structural shortfall.
The alternative for the same cut: a faced wall where drainage has to be engineered in behind it
Backfill behind a gravity structure is placed in layers so it does not settle away from the face
Where the cut is steeper than a gravity wall can hold, the face has to be nailed instead
Basket sizes and step-backs come off the slope assessment, not off a catalogue
