Shotcrete for excavation faces, slopes and facings
Shotcrete is concrete or mortar sprayed at high velocity onto a surface, where it compacts on impact. Reinforced with mesh or fibres, it forms the facing for soil nail walls and protects slopes, rock faces and excavations.
Suitable ground conditions and applications
Can be considered where…
- Facing for soil nail walls.
- Temporary support of excavation faces.
- Slope and rock face protection.
- Lining and repair of concrete surfaces.
Limitations
- Quality depends on the skill of the nozzle operator.
- Rebound and overspray must be managed.
- Shotcrete must be cured carefully in hot climates.
- Drainage behind the facing must be provided.
Suitability is confirmed from the site investigation and the performance requirement.
How it works
Concrete is pumped to a nozzle and sprayed with compressed air, either premixed with water (wet-mix) or with water added at the nozzle (dry-mix).
It is built up in layers to the design thickness over mesh or with fibres, with drainage behind the facing, then cured.
Design inputs
- Thickness and strength class.
- Reinforcement: mesh or fibres.
- Drainage behind the facing.
- Exposure conditions.
Trial and calibration
- Test panels sprayed and cored for strength.
- Nozzle operator competence confirmed.
Execution controls
- Surface preparation.
- Thickness checked with gauges.
- Layer build-up and rebound management.
- Curing, especially in hot weather.
- Daily records.
Verification and acceptance
Design intent, production control and acceptance verification are kept separate, so it is always clear what was required, what was done and what was proven.
What is required
Strength and thickness requirements agreed with the consultant.
What was done
Records of mix, thickness and curing.
What was proven
Cores for strength and thickness; test panels; visual inspection.
Deliverables
- Method statement
- Mix design
- Test panel results
- Daily records
- Core test reports
Common questions
What is shotcrete used for?
As the facing of soil nail walls, for temporary support of excavation faces, and to protect slopes and rock faces.
What is the difference between wet-mix and dry-mix shotcrete?
In the wet-mix process the concrete is mixed with water before pumping. In the dry-mix process water is added at the nozzle.
How is shotcrete quality checked?
With thickness gauges during spraying, test panels, and cores tested for strength and thickness.
Discuss whether Shotcrete fits your ground conditions.
Share the site location, the investigation report and the performance requirement.