Safety in excavations and trenches is one of the critical areas of construction risk prevention, owing to the high risk of collapse and workers being buried. The inherent instability of the ground, combined with loads accumulating at the edges, makes work in bulk excavations and trenches an activity of particular danger.
In the daily pace of the earthworks phase, the lack of prior ground characterisation, accumulated water or the vibration of heavy plant tends to cause unforeseen collapses of the walls. Entrapment at the bottom of a trench has catastrophic consequences within minutes if no retaining protection is in place.
To ensure effective excavation and trench safety, it is necessary to install certified shoring, respect material stockpile stand-off distances and provide continuous supervision at the work face.
In this guide we cover the mandatory preventive measures, ground control and the digitalisation of inspection reports. To frame these measures within the project's overall plan, see our guide to site safety.
Main occupational risks on excavation works
Bulk excavations and trenches present a variable risk dynamic depending on the type of ground, the weather and the depth reached.
Identifying the causes of instability is the first step to applying retaining measures in advance.
Recurrent hazard factors
- Collapse or burial: Sudden failure of the walls due to a lack of shoring, unauthorised vertical cuts or water seepage.
- Falls from a height: Absence of perimeter guard rails or unmarked accesses around open trenches.
- Being struck or trapped by plant: Buckets or excavators entering the working radius of operatives inside the trench.
- Gas inhalation or asphyxiation: Accumulation of heavy gases in deep excavations that lack adequate ventilation.
Preventive measures and ground retention systems
The choice of protection method depends on the depth of the excavation, the type of ground and the presence of adjoining structures.
From a depth of 1.30 metres (or sooner in unstable ground), it is mandatory to shore the works or cut the ground to a suitable natural batter slope.
Protection methods for walls and edges
- Metal shoring and timber frames: Modular protections or metal panels that hold back the horizontal thrust of the ground.
- Slope battering: Reworking the ground cut to a suitable angle to prevent sliding under gravity.
- Safe stand-off distance for stockpiles: Keep excavated material, equipment and plant at least 2 metres from the edge of the excavation.
- Safe accesses and walkways: Compliant ladders extending 1 metre above the top edge, and walkways with guard rails to cross over trenches.
Supervision and the role of the safety officer in excavations
Owing to the high risk of collapse, the law requires constant technical presence to audit ground conditions before operatives descend.
Continuous vigilance prevents accidents at any sign of cracking or water seepage.
Responsibilities at the work face
- Mandatory presence of a safety officer: Mandatory appointment of safety officers on site during all excavation work of particular danger.
- Checking PPE: Ensure operatives wear the necessary mandatory PPE in construction (helmet, reinforced boots and high-visibility vest).
- Control of perimeter signage: Demarcate the trench edge with rigid mesh barriers and site safety signage.
Digitalising trench and excavation inspections
Reviewing the condition of the shoring and inspecting for cracks after rain requires a daily documentary record.
Through site safety management software, the technical office receives the results of field checks in real time. This helps keep the mandatory documentation on a construction site organised.
Step 1: Carry out the visual inspection before entering the work face. Check for cracks, water seepage or sinkholes before authorising access. Step 2: Complete the checklist in the app. Fill in the site safety checklist, photographing the shoring and perimeter guard rails. Step 3: Report non-conformities instantly. Issue a corrective order if plant is detected stationary less than 2 metres from the edge. Step 4: Sign and validate the safety report. File the digital report with a signature and GPS location to evidence the inspection carried out.
How Trowel helps
| Problems | How Trowel solves it |
|---|---|
| Loss of control over the daily review of trench walls and shoring | Daily inspection record from your mobile with geolocated photos of the ground's condition |
| Lack of traceability of the safety officer's presence in excavations | Sign-in and vigilance reporting with a digital signature directly in the app, in the Health & Safety module |
| Failure to comply with soil stockpiling at the trench edge | Automatic alerts generated for the foreman to remove heavy loads from the edge |
You can see the technical detail of each module at Trowel Academy.
Frequently asked questions
From what depth is it mandatory to shore a trench?
The regulations establish the obligation to shore or batter from a depth of 1.30 metres, or at shallower depths if the ground is unstable or there is seepage.
At what distance from the trench edge should materials be stockpiled?
Excavated materials, tools and plant must be placed at a minimum distance of 2 metres from the edge to avoid overloads that could cause collapses.
Who should inspect the excavation after a spell of rain?
The safety officer or prevention technician must carry out a thorough inspection of the ground and the shoring before allowing workers to re-enter the work face.
Conclusion
Strict control of excavation and trench safety through certified shoring, edge demarcation and active supervision prevents accidents caused by ground collapse. Prevention in earthworks demands daily discipline at the work face.
Digitalising verification reports and the tracking of findings ensures a controlled and informed environment. If you want to modernise the management of safety in your excavations, request a free Trowel demo.
You may also be interested in
- Safety officers on site →
- Site safety checklist →
- Mandatory PPE in construction →
- Site safety signage →
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