Post by Edward HennesseyBruce probably knows better than I do but the constraining factor for
you would be what is available in your area. Call rental
yards and ask them what they have along that line. Remember, when
trying to sort rental rates for different machines..
that bigger is usually better and much faster.
I have no idea what would be available in China, but I see a BUNCH
of Excavators on the news out of the Quake Zone, so I know they have
them there. The Concrete Breaker attachments are like a JackHammer
attached to the business end of the Excavator Arm. If it was "Me",
I would look seriously into maybe using a 1.25 inch. Rock Drill, and
drilling down oh, say 2 - 3 meters, with a series of holes in the shape
of the area to be excavated, and then load the bottom of the holes with
something like "Individually Capped 1/4 Stick Charges of 1" Tovex". Then
cap, and tamp the holes with moist sand. This would shatter the
substrate down at the bottom, while leaving, the surface undisturbed, or
just slightly cracked. It would make excavating, a whole lot easier,
while preventing ANY Fly Debris, from leaving the surface.
I did a job at a location in Alaska a few years back, where they ran
into a WWII Foundation made of Seven Bag Concrete with 30# Rebar/CuFt.
they needed to run a Sewer Line thru the foundation, but it was in a
driveway between to two, Two Story Bunkhouses, with a LOT of Glass
windows facing the driveway. I had the MuckMen drill the foundation, as
above with five Holes, loaded as above, and tamped with wet sand.
Covered the whole excavation with Wet Sand, and topped it with a Steel
8' X 8' X 1/4" steel plate. The Owner's foreman was very concerned,
about the windows, and I bet him $50US that there would be No Fly at
all. Set it OFF, and there was just a "Whomp" that you could barely feel
in your feet, and a small wisp of smoke that boiled up thru the sand.
Moved the Plate, and the Backhoe Operator dug down to the foundation,
with the hoe. He caught the bucket teeth on the ReBar, but the
foundation was just gravel. Took a cutting Torch to the Rebar and there
was a nice trough thru the old Foundation for the Sewer Line. I got the
Cigar, and the $50US bet. The trick to all of this, is to use Lots of
holes, and very little, reasonably fast Powder, with each individual
charge, individually capped, and the timing set for an outside to inside
detonation.
This isn't Rocket Science, but it does take an Experienced Powderman
to do the figuring, and live with the consequences.
--
Bruce in alaska
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