RAMS and method statement for excavation and groundworks

Excavation looks routine until the ground moves or a machine finds a buried cable. Two of the most serious risks on any groundworks job, collapse of the sides and contact with underground services, can kill in seconds and give almost no warning. That is why a risk assessment and method statement for excavation is scrutinised. This guide covers what a groundworks RAMS should contain on a UK site, from a shallow drainage run to a deep foundation dig.

What a RAMS for excavation needs to cover

Describe the actual dig: its depth, length, the ground type, the water table, what services are known to cross it, the plant being used and whether people will enter it. A 600mm deep drain trench in firm ground is a different risk from a deep pile cap in made ground next to a road. The document should show that the ground and the services have been assessed, not assumed, and that the support method suits the conditions.

The main hazards of excavation and groundworks

• Collapse of the excavation sides burying or crushing anyone in the dig.
• Underground services: electricity cables, gas, water, telecoms and fibre, causing electrocution, fire, explosion or flooding.
• People and plant falling in, and materials or spoil falling on people below.
• Plant and pedestrian interface: excavators, dumpers and reversing vehicles near people on foot.
• Water ingress and flooding of the excavation.
• Hazardous or contaminated ground and hazardous atmospheres in deeper or confined excavations.
• Adjacent structures undermined by the dig, and overhead lines above the machine.

The control measures a reviewer expects

Tie each control to a hazard above.

• Prevent collapse: batter back to a safe angle, bench, or install shoring or a trench box before anyone enters, chosen by a competent person for the ground.
• Locate services first: current plans, a cable avoidance tool and signal generator, marking up, and hand dug trial holes to confirm positions before machine digging near them. Treat unknown services as live.
• Stop falls in: edge protection, barriers and covers, with spoil and materials set back from the edge.
• Separate plant and people: exclusion zones, banksman where needed, and safe access such as a secured ladder into the dig.
• Manage water: pumping and a plan for sudden ingress and rain.
• Assess the atmosphere and ground where contamination or a confined space is possible, with gas monitoring and a separate confined space plan if triggered.
• Protect adjacent structures and keep the machine clear of overhead lines.
• Inspect the excavation at the start of each shift, after heavy rain and after any fall of material, and record it.

The method statement sequence for excavation

1. Confirm service plans, survey and mark services, and complete a permit to dig if the site uses one.
2. Set out the dig, establish exclusion zones and safe access, and brief the team with a toolbox talk.
3. Hand dig trial holes to prove service positions before any machine excavation near them.
4. Excavate in a controlled way, keeping spoil set back and installing the chosen support or batter as you go, not after.
5. Inspect the excavation before anyone enters, and record it. No entry into an unsupported or uninspected dig.
6. Carry out the groundworks with the support in place, managing water and monitoring the sides.
7. Backfill or slab as planned, removing shoring in a controlled sequence.
8. Reinstate, remove barriers only when safe, and complete the records.

Where excavation RAMS usually get rejected

• No service location method, or a plan to machine dig straight away without trial holes.
• Support method not specified, or left to be decided in the trench.
• No inspection regime for the excavation.
• Plant and pedestrian separation not addressed.
• No plan for water, contaminated ground or a possible confined space.
• A generic sequence with no set out, no proving of services and no support step.

Frequently asked questions

When does an excavation need support?

Any excavation that people enter should be assessed for the risk of collapse. Ground can fail with little warning, so battering back to a safe angle, benching, or shoring and trench boxes should be used where a person could be buried or struck by a fall of material. A competent person decides the method for the ground conditions.

How do I avoid hitting buried services?

Get up to date service plans, use a cable avoidance tool and signal generator to trace and mark services, hand dig trial holes to confirm positions, and treat any unidentified service as live. Brief the team on the marked positions before machine digging near them.

How often should an excavation be inspected?

An excavation that people work in should be inspected by a competent person at the start of each shift before work begins, after any event likely to have affected its stability such as heavy rain, and after any accidental fall of material. The inspection is recorded.

Is this legal advice?

No. This is a plain-English working summary to support site teams. For the detail see CDM 2015 and HSE guidance on excavations and underground services such as HSG47.

Related guides: permit to work, COSHH assessment, and the CDM 2015 regulations explained pillar.