Can Anyone Tell Me The Minimum Distance To Place Spoil From A Trench When Using A Backhoe Or Digger.?
3 Responses to “Can Anyone Tell Me The Minimum Distance To Place Spoil From A Trench When Using A Backhoe Or Digger.?”
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October 4th, 2009 at 12:02 am
Health & safety regulations are ‘contingent’. That means that what DOES NOT CAUSE an accident is, by definition, safe.
Legal standards for works are set by the specialised overseeing bodies for those works; so best practice (and recommended practice) will vary according to the purpose (say, drainage or laying cables).
In practice, the ‘safe’ limit is set by a properly trained health & safety professional; if they say something is unsafe (far more likely than saying something is safe), then it is legally deemed to be so. Ignore them at your peril !
The Health & Safety Executive website (www.hse.gov.uk) might list something specific to the works you have in mind.
In engineering terms, load is distributed outwards at between 60 and 45 degrees below the material doing the loading. This is an approximate rule of thumb; different soils will perform differently.
The rule of thumb means that none of the spoil should be closer to the trench, than the trench is deep. In practice, the weight of the undisturbed earth next to the trench is often sufficient to collapse the trench, without any help from added spoil.
Therefore any trench DEEPER THAN IT IS WIDE is considered to need shoring, with struts across to hold the shoring boards firm.
One common mistake is to prop the boards at a certain depth, and then dig the same amount further before adding props; this is EXTREMELY DANGEROUS because the quantity of earth trying to collapse the trench MULTIPLIES as the depth ADDS.
Another danger is the weight (and vibration) of the digger, which is also trying to collapse the earth near the trench it’s digging. Again, it is dangerous to excavate any closer to the digger than the depth of the excavation (although a concrete surface can mitigate the problem, and soft or variable ground can make it worse). If the trench is dug at 45 degrees towards one side of the excavator, this allows a wide arc on the opposite side for clearing the spoil.
The short answer is that placing the spoil any closer than the maximum distance possible with the backhoe, CAN be considered irresponsible. The safest method is to truck it away, even temporarily, as this also provides a clearer working area. Needless to say, the MOVING load of the truck is even more dangerous near the trench than a static load would be, so it should be kept as far away as it is possible for the backhoe to reach.
October 4th, 2009 at 2:09 am
no legal requirement, the distance goes on the material and the angle of repose of that material. A safe manner of work would be expected to be adopted.
October 4th, 2009 at 2:43 am
FAR ENOUGH SO IT DOES NOT FALL BACK IN