ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Shout Box
Recent Posts
VDE 0100 to introduce AFCIs
by sparky. 01/20/18 05:09 PM
MRI LED lights dimmer control replacement - wow!
by Potseal. 01/19/18 08:52 PM
Video: Inventor of the GFCI self-testing shocks
by Bill Addiss. 01/17/18 11:11 PM
FPE in Germany
by HotLine1. 01/17/18 07:07 PM
Fujifilm Recalls Power Adapter Wall Plugs
by Admin. 01/16/18 07:04 PM
New in the Gallery:
Housebilding DIY wiring
SE cable question
Who's Online Now
0 registered members (), 6 guests, and 9 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Trench Safety #115824
12/23/03 06:34 PM
12/23/03 06:34 PM
Admin  Offline
Joined: Oct 2000
Posts: 3,481
[Linked Image]

[Linked Image]

[Linked Image]
Thought you may like some pics of trenches, and why trench boxes are required. At Dulles, we enforced VERY heavily the use of trench boxes in ANY trench over 3' deep. The only reason to step outside one was to pick up that last paycheck, cause if you stepped out, it would be your last. We did have a tunnel collapse while I was there, a bit different than a trench cave in, but a life was lost none the less.

You can see the type of soil we were dealing with, called fractured, or degraded rock. I've had people argue it was Class A soil just after they dug the hole, while we were arguing, the wall would collapse, END of argument.


Tools for Electricians:
Re: Trench Safety #115825
12/27/03 05:41 AM
12/27/03 05:41 AM
Trumpy  Offline

Joined: Jul 2002
Posts: 8,231
SI,New Zealand
I've never seen soil of that colour before, apart from in Australia.
Where did you say this site is?. [Linked Image]

Re: Trench Safety #115826
12/27/03 09:46 AM
12/27/03 09:46 AM
George Corron  Offline
Joined: May 2001
Posts: 717
Lorton, Va USA
It's about 30 miles SW of Washington, D.C. at Dulles International Airport. The soil is called degraded rock, you can see it in some of the pictures.

You literally have to beat it out, using machines called Hoe-Rams, there is no digging of this stuff initially. Once exposed to air, rain, snow, it becomes muck. You can see in the first picture the way it looks when used for backfill.

When it degrades, it becomes some very nasty clay when put back properly. We would not certify it for backfill on a good deal of the property causing contractors to import stuff from other parts of the region.

When we set manholes, or any other critical structure, we most often backfilled with a concrete (cementitious material for you afficianados) called "Flow fill" or "Slurry" mix. We made our own concrete on site most of the time. As you can see, all ductbanks had to be encased in 4,000 psi concrete and have a rebar envelope.

Re: Trench Safety #115827
12/27/03 09:19 PM
12/27/03 09:19 PM
mvpmaintman  Offline
Joined: Sep 2003
Posts: 123
Manhattan, Kansas, USA
Looks like the stuff in western Wyoming too. Spring thaw used to make stuff we called Hershey's,$#!^ had a fleet of vac trucks to clean it up. LOL

Re: Trench Safety #115828
12/29/03 08:34 PM
12/29/03 08:34 PM
ThinkGood  Offline
Joined: Aug 2002
Posts: 1,081
Milwaukee, WI

A bit off-topic, but do you ever find anything interesting when you go digging out that much of an area?

Re: Trench Safety #115829
12/29/03 09:13 PM
12/29/03 09:13 PM
wa2ise  Offline
Joined: Nov 2002
Posts: 785
Oradell NJ USA
[quote]but do you ever find anything interesting when you go digging out that much of an area?[quote]

My brother did construction work (steelwork inspector) at the WTC when it was being built. The management said something to the effect that if someone finds something, it's yours, take it home, get it outta here. "And I dont want to know about it". They didn't want the project delayed by archeolgists digging around the site. My brother never heard if anyone ever did find anything.

Re: Trench Safety #115830
12/29/03 10:09 PM
12/29/03 10:09 PM
ga.sparky56  Offline
Joined: Nov 2002
Posts: 558
young harris georgia usa
I do some small scale excavating,ug power,water,septic etc.

I've found some interesting arrowheads and pottery over the years.


Re: Trench Safety #115831
12/29/03 11:30 PM
12/29/03 11:30 PM
George Corron  Offline
Joined: May 2001
Posts: 717
Lorton, Va USA
At Dulles, no, it was a farm for a LONG time, then it became an airport.

The Pentagon was something a bit different. It was built on an old airport, junkyard, landfill, whatever human refuse was buried there. One Steamfitter took home an INTACT model T. It was rusted, all cloth gone, but all was there.

Handmade crowbars from the original construction - they must have had someone making them on site, we had pictures of crews with them, OLD pottery, OLD china, we dug up lots of interesting stuff there.

For some reason, they were sorta funny about taking pics of the place [Linked Image]


2017 Master Electrician Exam Preparation Combos
2017 NEC Electrician
Exam Prep Combos:
Master / Journeyman


Member Spotlight
Washington...Not DC
Posts: 222
Joined: March 2005
Show All Member Profiles 
Top Posters(30 Days)
Admin 20
sparky 16
Potseal 15
Popular Topics(Views)
243,572 Are you busy
180,371 Re: Forum
170,846 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.6.1
(Release build 20180101)
Page Time: 0.023s Queries: 14 (0.005s) Memory: 0.9934 MB (Peak: 1.1529 MB) Zlib enabled. Server Time: 2018-01-21 06:44:32 UTC