Explorative backhoe trenches and personal safety
Explorative backhoe trenches and personal safety
(OP)
Hi,
browsing the past threads (I thing the slope eng forum) I came across a discussion on backhoe trenches used to investigate the fine details of (superficial) stratigraphic sequence. In my country (Italy) that's a pretty common way to proceed. I've got some serious doubts though upon the safety of this practice, supported by past experience and recounts; specifically, I've seen quite a few backhoe trenches, of various depth, collapse (entirely or partially) in a time ranging from one to 5-6 seconds.
Moreover, there was a local professor of geology who worked a lot with explorative trenches. Probably he was aware of the hazard, because often he had other geologists gone inside the trench and collect litho-stratigraphic info. One day he was surprised by a sudden wedge failure while standing on the trench edge, and was dragged down and buried alive.
Now they organize lectures to his memory.
Believe me, I too would love to get my hands dirty as much as possible but when approaching those trenches I'll just have a look from above, keep my hands clean and walk away safe and sound!
My question is: do you guys follow any safety rules when descending into trenches? Do you routinely use protections or devices of sorts? How do you assess the stability of a trench and be so sure about it to potentially endanger your life ?

browsing the past threads (I thing the slope eng forum) I came across a discussion on backhoe trenches used to investigate the fine details of (superficial) stratigraphic sequence. In my country (Italy) that's a pretty common way to proceed. I've got some serious doubts though upon the safety of this practice, supported by past experience and recounts; specifically, I've seen quite a few backhoe trenches, of various depth, collapse (entirely or partially) in a time ranging from one to 5-6 seconds.
Moreover, there was a local professor of geology who worked a lot with explorative trenches. Probably he was aware of the hazard, because often he had other geologists gone inside the trench and collect litho-stratigraphic info. One day he was surprised by a sudden wedge failure while standing on the trench edge, and was dragged down and buried alive.
Now they organize lectures to his memory.
Believe me, I too would love to get my hands dirty as much as possible but when approaching those trenches I'll just have a look from above, keep my hands clean and walk away safe and sound!
My question is: do you guys follow any safety rules when descending into trenches? Do you routinely use protections or devices of sorts? How do you assess the stability of a trench and be so sure about it to potentially endanger your life ?






RE: Explorative backhoe trenches and personal safety
In the U.S. there are safety requirements because of the potential for failures in open trenches. OSHA (Occupational Safety and Health Adminstration) has published guidelines based on soil type and depth of excavations. Trench boxes are most commonly used for support. You should browse the OHSA website and download the appropriate information.
Glen
RE: Explorative backhoe trenches and personal safety
RE: Explorative backhoe trenches and personal safety
After all, Safety First!
Please see FAQ731-376 for great suggestions on how to make the best use of Eng-Tips Fora. See FAQ158-922 for recommendations regarding the question, "How Do You Evaluate Fill Settlement Beneath Structures?"
RE: Explorative backhoe trenches and personal safety
I'm aware of the OSHA regulations (similar ones are enforced in Italy) but I'm not aware of any field engineer or geologist using shields, boxes or cages for trench exploration. Some of these contraptions would cover the trench walls and the valuable lithologic/stratigraphic details displayed, others are downright unconvenient and time-consuming for such a supposedly expeditious recognition. Only time I read they were extensively used was in some huge dam project in Canada, people used steel cages going down explorative shafts (drilled thru rock. mainly).
Benching the excavation appears sensible, only I reckon it makes the soil structures less evident.
RE: Explorative backhoe trenches and personal safety
RE: Explorative backhoe trenches and personal safety
I admire BigH's honesty and must admit I've been in some trenches and confined spaces without safety equipment too. But, just because I was lucky enough to survive my younger stupid days, doesn't make it right, it just makes me lucky. I've since learned that working safely may take a little longer, I at least get to finish the day!