Components, systems and materials › Slope protection and rockfall › Rockfall drapery mesh
Rockfall drapery mesh
What it is
Drapery is a steel wire mesh laid over a rock or soil slope. Unsecured drapery hangs freely from the crest and guides falling stones down behind it; secured (pinned) drapery is tied to the slope with anchors and holds loose material in place.
Where it is used
Cut slopes along highways and railways, quarry faces and portal faces where many small to medium blocks loosen over time.
How it works
With unsecured drapery the mesh does not stop rocks from detaching; it controls them, so they slide down between mesh and slope into a ditch at the toe instead of bouncing onto the road. With secured drapery, a grid of anchors and tensioned ropes presses a high-strength mesh against the face, so the mesh carries the load from loose blocks into the anchors.
Types
- Unsecured drapery with top anchors only
- Secured drapery with anchor grid and boundary ropes
- Hybrid drapery with an open bottom and a catch fence
Materials
Double-twisted hexagonal wire mesh or high-tensile steel wire mesh, with zinc or zinc-aluminium coating and sometimes a polymer coating; wire ropes; grouted bar anchors with spike plates.
Choose the system from the block size and the instability mechanism. Unsecured drapery needs a toe ditch large enough to collect the material and must be cleaned. Secured drapery is designed so that the mesh, its punching resistance at the plates, and the anchors can carry the unstable volume between anchor rows.
Installation and QA steps
- Scale loose rock off the face
- Install crest anchors and top rope
- Unroll mesh panels down the slope and lace panel edges together
- For secured systems, drill the anchor grid and tension plates against the mesh
- Clean or form the toe ditch
- Ditch full so rocks escape onto the road
- Mesh torn by large blocks it was not sized for
- Lacing wire undone between panels
- Coating damaged and mesh corroding
Related
Generic description for education. We do not name, endorse or compare manufacturers or products.
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