On site
What is an excavation?
An excavation is any cutting or trench. Collapse, falls into it, and striking buried services are the three risks, and they are managed by support, edge protection and service location.
Ground collapses without warning and a very shallow trench can kill, which is why support or battering is not reserved for deep excavations.
Buried services are located by drawings, by detection equipment and by safe digging practice together. Any one of the three alone is routinely wrong.
Excavations require inspection by a competent person at defined points, including before each shift and after anything likely to have affected stability.
What goes wrong in practice
- Shallow trenches left unsupported on the basis of depth alone.
- Service drawings relied on without detection or trial holes.
- Inspection done at the start of a job rather than before each shift.