How to Build a Gabion Wall

1. Storing the bundles

Gabions arrive folded flat in bundles with the lacing wire. Stack no more than four bundles high, on level ground, on wooden sleepers so the mesh and selvedge are not damaged. Keep them off oil, chemicals and abrasive surfaces.

2. Preparing the foundation

• Excavate to the level on the drawing. If firm ground is not reached, stop and refer to the engineer.
• Remove soft material and debris; fill loose pockets with compacted granular material.
• Clear standing water. Where the site cannot be dewatered, gabions can be placed under water.
• Compact the base — IRC:SP:116-2018 calls for a vibratory roller of 8–10 t and at least 95% of modified Proctor density.
• Mark the line of the front face.

3. Assembling each box

• Unfold the box on a hard, level surface and straighten the panels.
• Lift the sides, ends and diaphragms and tie the top corners with the heavy selvedge wire.
• Check that all four corners meet and the box is a true rectangle before it goes in place.

4. Lacing — where walls are won or lost

Lace every edge in one continuous run, starting at a top corner, passing the wire through the mesh with alternate single and double loops at every mesh opening (roughly 100–125 mm). Secure the ends at the corners and turn them into the box.

Do not use short individual ties. Steel rings applied with a ring tool, as allowed by IS 16014, are the alternative. Adjacent boxes are laced to each other along every touching edge, top and bottom — the wall has to act as one mass.

5. Filling in layers

• Fill with stone larger than the mesh opening, packed for the fewest voids. Choose and hand-place the face stones for a neat, tight face; with quarried stone, turn a flat face outwards.
• In a 1 m high box, fill to one third, fit internal tie wires across the box, fill to two thirds, fit a second row, then complete. A 0.5 m box needs one row at mid-height. The ties stop the face bulging.
• Never let one cell get more than 300 mm higher than the cell beside it — fill neighbouring cells in step.
• Overfill by about 25–50 mm to allow for settlement.
• A pipe or frame formwork against the face keeps bulging within tolerance and gives a much better finish.

6. Closing and the next course

Fold the lid down, lace it to the top of every side and diaphragm, and lace the next course of boxes to the one below. Joints in the course above should be staggered over the course below, like brickwork. Lay the filter geotextile against the back and place and compact the backfill as the wall rises.

A quick quality check

You can check the filling by weight. At around 35% voids a packed gabion weighs roughly 1.7 tonnes per cubic metre, so a 1.5 × 1 × 1 m box should come to about 2.5 t. A box much lighter than that is loosely packed and will settle and bulge.

Questions