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Posted by tom on October 26, 2006, 10:08 am
Rounded things are usually more resistant to exterior forces than
interior forces. Ever watch a baby bird poke its way out of its
eggshell? Tom
HeyBub wrote:
> At least that's what the city calls it.
>
> But you may be interested in their technique.
>
> At one end of the block, the workers dug down about eight feet to the
> original sanitary sewer line. This line is a concrete pipe, about ten inches
> in (outside) diameter with 3/4" thick walls.
>
> Into this concrete pipe, the city pushes a PVC (let's call it PVC - it's
> probably depleted uranium) pipe that's actually larger than the original
> concrete pipe. They hammer this new pipe hard. The new pipe travels at least
> 1000' (to the next work-hole), fracturing the original concrete pipe as it
> goes. They did some serious hammering - the ground shook. It frightened my
> fish. Beer in the fridge went bad.
>
> The city then goes into each backyard with an itty-bitty backhoe, digs down
> eight feet and connects - through some magical process I haven't seen yet -
> each house to the new pipe.
>
> Prior to all this digging and hammering, the workers attached some
> sophisticated electronic gizmo to the sewer, water, gas, and telephone
> cables (in turn) and spray-painted the grass with mystical runes - of
> different colors - to mark where these underground utilities traveled. The
> electrical lines are above ground.
>
> My son did ask one of the workers what happens to the, ah, sewage between
> destruction of the old pipe and the eventual reconnection to the new pipe.
> The official response was: "Oh, well..."
>
> Anyway, the part that amazed me was the pushing, and resultant cracking, of
> the original pipe by the new PVC conduit. The military should consider this
> plastic pipe as tank armor.
>
> The original concrete sewer pipe was laid, I imagine, when this sub-division
> was originally built up: in the 1960s.
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