I am installing a 48" galvanized pipe for a residential driveway crossing a creek. Right now the creek is dry but there is evidence of erosion on the upstream side. My question is can I use 21A stone (crusher run) to bed the sides of the pipe. Normally I would use 57s (clean stone) because I don't have to compact it. I don't want to use 57s because I don't want the creek water to find its way through it. Or should I backfill with clean dirt (our local dirt has lots of clay) that would block the water. I would rather work with the stone all the way up because it would be easier and quicker and I feel gravel will provide better support for the pipe and prevent deflection. Thanks in advance for your input.
end flume is usually laid on existing soil... depends on the engineer the end flume is compacted soil to seal the ends...with enough room left to place rip rap....some times a fabric cloth...then rip-rap or quikrete bags ....both ends of the flumes are dug down then rip rapped in front of the flumes pipe is rocked on bottom... then about half way with sand.. then compacted dirt... once in a while the dreaded flowable fill.... one plant thought it was the cat's meow several years ago... until recently when plant additions started going in... tuff stuff and near impossible to dig.. even though the concrete companies advertised it as easy to remove...
I would set in the dirt at hand and then do what you can to armor it up with 3-6" (gabion) and you'll be fine. Pj