Retained excavation
Geotechnical and Structural
- Ground
- Cut face, mixed soils
- Method
- Slope stability modelling
- Scope
- Soil nails, mesh, shotcrete
- Outcome
- Designed, staged, signed off
A cut face has to be held from the moment it is opened, and the ground decides how. Testing came first: the profile through the cut set the loads the face would shed, and the retention was designed against those numbers rather than against a detail that worked on the last job.
The face is nailed on a designed grid, meshed, and shotcreted in passes. Timber walings spread the load into the nails while the concrete gains strength. The sequence matters as much as the design, so the construction stages were drawn as part of the package rather than left to the site to work out.
The geotechnical investigation, the retaining design and the producer statement came from the same practice. Nothing waited on a second consultant to agree with the first.
The sprayed face carries the nail heads while the block wall is built off the toe
The pass thickness is set by the design, not by how the face looks when it is wet
Anchor plates set out across a completed face at the spacing the design called for
Fill behind the completed retention is placed in layers and tested as it goes
