Construction Health and Safety Consultancy and CDM Adviser Services

A Hole Lot of Trouble – Keep Your Excavation Trenches Safe!
Posted by David Cant on September 2, 2014

Excavation Safety for your Business

construction siteHe’d been told the water had been cut off.

Last month a worker in Moray stood in a 1.3-metre deep excavation trench – not even a very deep one – and happily got to work cutting a section of cast iron water piping.  Suddenly, water exploded out of it and he leapt to the other side.  But not far enough as the wall collapsed…

This unfortunate incident illustrates the two main causes of injury in excavation sites; bad preparation and poor communication. Think it’s an overstated risk? Just remember this;

Just one cubic meter of soil can weigh One Tonne

We don’t want that falling anywhere near us!  This particular construction company got a whopping fine for the worker’s injuries – a crushed leg (and fortunately not worse).

But if you’re aware of the safest procedures for dealing with those necessary holes in the ground every site has, you won’t ever need to pay one.

The risks in excavations

As in the story, the biggest risk is collapsing walls, which can bury people.  Then materials, tools, bits and bobs falling off the lip of the hole, and lastly vehicles and people falling into poorly marked out holes.

Your golden rule to remember

You can’t rely on any ground to stand on without support in all circumstances.  Support, support, support.

What the commercial clients have to do

Of course it all begins with the info.  Commercial clients must give contractors all details of; ground conditions, underground water course or structures, and any existing services.

Then you, the contractor, can take the;

Eight Steps to Ensuring Safe Excavations

  1. Check closeness of other site structures

Take great care that your tunnel, pit or trench doesn’t come anywhere near the base of scaffolding, building foundations or any other structure.  You don’t want to undermine anything when you’re underneath it!

  1. Set up temporary support

Before getting stuck into digging any pit, trench or tunnel, carefully plan the support to help during digging.  And make sure it’s all there ready on hand – no cutting corners!

  1. Batter those walls well

Support the sides of the excavations with sturdy battering.  Pay attention to the angles.  For example, in granular soils the angle of the slope can be slightly less.  In wet ground it should be greater.

  1. Protect the edges from falling materials

The most common things to fall into a trench and cause injury is spoil heaps from the digging.  Make sure you use sturdy edge protection.  Toe boards, and projecting trench sheets or box sides will work.

  1. Wear head protection

It might not seem like there’s much above you, but like anywhere on a work site, wear head protection!

  1. No parking near to the edge

Of course, make sure no vehicles or plant machinery are parked anywhere near the edge of the excavation.  It might be all it takes to make an already loose wall collapse.

  1. Stop people falling in!

Another area of injury is workers or even pedestrians walking and falling into poorly marked out trenches.

Give any excavation nice big clear barriers with guard rails and toe boards right at the lip.  Fabricated guard rail assemblies connecting to the sides of trench boxes.  And you can use the supports extending up and past the top of the trench to show clearly.

  1. Get proper inspection

Like anything on a worksite, get an experienced, well-trained person to come and study it, making sure it’s safe.  And do this at the beginning, and after any event that might have destabilized the trench or tunnel – perhaps a vehicle coming near the edge, or anything falling in.

With these precautions in place, you’ll be digging safe and sound.

Have you got any queries about excavating?

Let me know!  Just comment below.


David Cant is a Chartered Safety and Health Practitioner extraordinaire. He has a wealth of Industry experience and is the MD of Veritas Consulting. David also Blogs about Health and Safety here Health and Safety Consultants

His aim is to flavour Health and Safety with integrity, served with a side of humour You can find David on - Twitter and Google also Linkedin

This post has been filed in: CDM Services, CDM Support, Construction Health and Safety, Health and Safety Consultancy


  1. Dougie
    September 2, 2014 at 1:21 pm

    Good piece
    I would add check excavation after heavy rain for changes.
    And to ensure there is always a means of escape ie a ladder which should be secured
    Yours Ex Digger driver of 25 years

    • September 2, 2014 at 4:36 pm

      Thank you for your contribution they are very valid points

  2. February 13, 2015 at 4:28 pm

    My husband is becoming an excavating contractor, and this is all really good information he should know before going out on his first day of work. I had no idea that soil could weigh that much! It frightens me to think that my husband is going out to work in these conditions, but it is reassuring to know that with proper safety precautions, he is a lot less likely to get injured while at work.

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