John:
Actually as someone mentioned previously, OHSA and most states require
shoring for excavations more than 4 feet deep if someone is to be in the
excavation. My previous discussion does not condone being in an excavation
without shoring if it is deeper than 4 feet or at a minimum benched per OSHA
requirements.
IF you are going to backfill please do not just use a hose to compact the
soil with water. This usually decreases the density of the backfilled soil
including the undisturbed soil adjacent to the backfill material. This is
opposite of what you want to do. IF you know the optimum water content of
the soil then wet it to that point, place it and mechanically compact in 8
inch lifts. This will give you the maximum density for the soil. This is
what you want. If you use too much water then the water is in the voids of
the soil,reducing the density of the soil and acts like a lubricant to allow
the soil to flow, i.e., quick sand. Dampen the soil and compact, is the rule
of thumb, don't place and water like a garden.
73
Hank Lonberg / KR7X
-----Original Message-----
From: teamw [mailto:teamw@quixnet.net]
Sent: Wednesday, March 21, 2001 05:40
To: towertalk@contesting.com
Subject: [TowerTalk] Re:[Tower Talk] Tower Base Construction
I agree with Joe Mowery AG4BW concerning hole digging safety. I am a retired
EMT and here in sand based Florida there are frequent collapsed trench
emergencies. Usually contracting companies and municipal workers are
involved, who should know better. They are frequently fatal.
Not shoring up excavations for the sake of convenience can be a serious
mistake. As noted by AG4BW, collapses can be sudden, soil (even sand) is
heavy and restricts movement and the weight of soil on the chest will
virtually prevent breathing (even if there was any air to breath down
there). By the time your buddy on the rope has dug you out or has alerted
the rescue services and they are on the scene it is too late in a high
percentage of incidents. Its no fun scooping sand from someones nose and
throat to try to establish an airway on a body thats been under the heap for
too long (more than 5-6 mins.)
>From my experience, back filling around a concrete block in sandy soil using
a water hose is a good way to restore the soil consistency to near that of
the undisturbed areas. Judicial tamping and water probably will help with
other types of soil as well.
de John AB4ET
teamw@quixnet.net
--
FAQ on WWW: http://www.contesting.com/FAQ/towertalk
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
--
FAQ on WWW: http://www.contesting.com/FAQ/towertalk
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
|