Excavations Flashcards
What is an excavation?
A trench cut into the earth
True or false:
The surrounding soil consistency and structure must be taken into consideration.
True.
Depending on what makeup the soil is, it will affect the structural stability of the trench and what methods must be used to prevent collapse.
What will affect the soil conditions, regardless of its structure?
Adverse weather conditions
Fill in the blanks:
The physical hazards of excavations are numerous:
* ___ falling onto people
* ___ & ___ falling into trenches
* People being struck by ___
* ___ nearby structures
* Contact with underground ___
* ___
- material(s)
- people
- vehicles
- plant
- undermining
- services
- access
Fill in the blanks:
The chemical hazards of excavations are numerous:
* ___ from vehicles
* ___
* contaminated ___ from former use
- fumes
- methane
- land
Where might the hazardous chemicals be in the excavation?
Collecting at the lowest point in the excavation, as they are heavier than air
There are many biological hazards associated with excavations:
* Leptospirosis or ___ disease from rat urine
* Previous ___ e.g. hospitals
* ___/sewers
* Rubbish & ___
- Weil’s
- use
- drains
- waste
What is the minimum depth that a trench must be to implement control measures?
1.2 metres deep
Fill in the blanks:
There are numerous control measures that can provide safety when working in an excavation:
* ___ ladder to provide safe access
* Guard ___ to prevent falls
* Exposed ___ are supported (eg. pipework)
* Supported by ___ & ___ to prevent collapse
* ___ boards must extend over the top of the excavation to act as ___ boards
- tied
- rails
- services
- timbering & props
- poling & toe
True or false:
Hard hats are optional when working in an excavation.
False.
Fired.
Name the methods that you might use to prevent vehicles from falling into an excavation.
Four methods
- Use signage
- Stop blocks to prevent vehicles from rolling back
- Guard rails and toe boards
- Keep vehicles away
Name the methods you might use to prevent people from being struck by plant.
Three methods
- Keep people and plant seperate
- Plant operators are to be fully trained and competant
- High visibility PPE
How might you prevent excavations from undermining nearby structures?
Three methods
- Check to see if you are affecting nearby foundations/ scaffolding
- Provide additional temporary support to affected structures if needed
- Contact a structural engineer for advice and to perform a foundation survey if needed
How might you prevent damage to undergound services when digging an excavation?
Five answers
- Dig trial holes by hand or if in doubt
- Look for signs of underground services
- Use cable locators and mark the ground
- Have emergency procedures & contact in place
- Use the service plan
True or false:
Underground plastic cabling cannot be detected
True.
In this situation, it would be best not to use industrial equipment until the wire has been located.
