Trench sheeting and timber shoring prevent trench walls from collapsing onto workers during excavation. These support systems must be installed progressively as the trench is dug and must never be removed while anyone is in the excavation. This talk covers the correct installation methods, inspection requirements, and the rules every operative must follow when working in supported trenches.
Key Hazards
Trench collapse burying workers due to missing or inadequate shoring
Timber struts failing under excessive ground pressure or vibration
Workers entering unsupported sections of trench ahead of shoring installation
Shoring removal before all workers have safely exited the excavation
Control Measures
Install trench sheeting and shoring progressively as the excavation advances in depth.
Ensure the shoring design is approved by a competent person and matches the ground conditions.
Inspect shoring systems before each shift and after any event that could affect stability.
Never enter any section of trench that does not have its support system fully installed.
Use adequately sized timbers or proprietary steel trench sheets as specified in the method statement.
Ensure struts are tightly wedged and bear firmly against the sheeting on both sides of the trench.
Remove shoring only from the bottom up as backfilling progresses, with no workers in the trench.
Keep surcharge loads including spoil heaps and plant at least one metre from the trench edge.
Record all inspections on the excavation inspection register and retain for the project duration.
Emergency / Rescue
If a trench collapse occurs, call 999 immediately. Do not enter the trench to dig out a buried worker as further collapse is likely. Direct the rescue from the surface and await specialist rescue services.
Remember
Shoring must be installed progressively as the trench gets deeper, not after the fact
Never enter any part of a trench where the support system is not fully in place
Inspect shoring before every shift and after rainfall, vibration, or any ground disturbance
Spoil heaps and plant must be kept at least one metre from the trench edge
Shoring is removed bottom-up during backfilling with no persons inside the excavation
Applicable Legislation: CDM Regulations 2015 · BS 6031:2009 (Earthworks) · Health and Safety at Work etc. Act 1974 · BS 5975:2019 (Temporary Works)