Just wanted to know if anyone would know why this is being done? Pipes are 24"( I think) concrete which will be used as a overflow system for a silt pond. I understand putting the black fabric around the joints, but surrounding them in concrete:beatsme
A few things come to mind: 1 - The engineer was concerned with seapage from the silt pond around the pipes, but it is interesting they only went to the spring line. 2 - That would definetely reinforce the pipe, although overkill.:beatsme 3. - Poor soils used for the dam construction 4 - Green "by the book" civil engineer?????:beatsme
I am with all 4 of those reasons. Mainly (and it's hard to tell from here,) poor soil conditions would be a good reason for the overkill in this picture. Looks like really sandy, light material that would permit seepage around the pipe, causing a blowout eventually. As for the green, by the book engineer...must be the same one we're dealing with on our job right now. Man, he gets around...:laugh
Same principal as anti-seep collars in Class B & C Berm Construction.The remaining area should be backfilled with material that has a high clay content.
Yeap there's a few of them fresh outta school, just got their feet dirty guys around here too. It has to be their way even though its a total waste of your time, money and not even possible to do unless your superman. But you go ahead a waste and entire day just so you can get the grade raised up 3/4" so it matches what he has on his little papers he always has to refer to. yeah it looks poor dirt but it's a good clay based materail, has not rained this month (at all!) so it's turned to a nice fluffy powder. Below the clay is solid rock so it's not like the pipes are going to settle. Who Knows...
That kinda looks like flowable rather than concrete. We used that alot in the medians on the interstate. Pete
maybe as a dead weight to help hold them in place in that soft sandy crap
Compaction It could be concreted 1/2 way up the pipe so you do not have to compact under the pipe. The cheapest solution would be flowable fill that way you do not have to use a wacker or the air compactor, With the clay being so dry it could be difficult to get 98% compaction. so this could be a cheaper and easier solution. I might even suggest this to my next pipe job.
It's to keep the pipe from moving. Over time you'll get a little settlement, plus some vibration when you have high water flow, and then the pipes will slowly start to pull apart. Unlike CMP where you have bands to fasten them together, this is an easier way to hold them. Or else drills holes and use rods. Then you have to send somebody in the pipe to put the nuts on.