I recently had a natural gas line replaced that had to be run under
two sidewalks for a distance of about twenty feet. The gas company
dug a hole on each side and "bored" a hole underneath. They used a
pointed steel device about three inches in diameter and three feet
long pulling two inch plastic pipe behind it. The plastic pipe was
attached to a large compressor on a trailer that they also used to
power their jack hammer. The device seemed to "vibrate" itself
through the very heavy clay soil laden with rocks. They told me that
there was a steel slug inside the device that was pushed forward and
back by the air pressure that banged against the front of the steel
tube and pushed it forward. When they reached the second hole they
just detached the plastic pipe from the device and it became the new
gas line. They also told me that the device could be found at larger
tool rental places.
While the water method might work okay in sandy soil, I've never had
any luck using it to drive ground rods in rocky clay soil. This thing
seems to be the compressed air powered, horizontal version of the
fence post driver (bong) and sledge hammer method that I always end
up using for driving ground rods.
Unfortunately, I didn't ask them what the "device" was called.
>I was wondering if anyone knows a way to dig a hole under a concrete
>driveway? The coax from my tower would either have to be elevated 12
>feet above the driveway , or buried under it. I am not going to cut a
>path through it! Doesn't the city lay pipe under sidewalks without
>damaging the existing concrete?
Jimmy Weierich, KG2AU <email@example.com>
Vestal, NY USA FN12xa
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