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Thread: dirt compacting

  1. #1
    Join Date
    Jul 2005
    Location
    ND
    Posts
    18

    Default dirt compacting

    Thanks alot for supplying this help online.

    My question is regarding compacting dirt. My installation requires me to dig down 11' with a backhoe with it being a 4' by 4' square. In the middle of this hole there will be a 10" i.d. pvc pipe with a 3/4" id galvanized water pipe in the middle of it. The deep hole and the 10" pvc pipe prevent the 3/4" water pipe from freezing. When I backfill all the dirt in the hole I have to provide a 5' by 5' concrete foundation with bolts in the concrete to hold down a horse waterer. The foundation is to support this horse waterer and the galvanized pipe is connected to the existing well waterline.

    I think you can picture what I have. I was wondering what the best way would be to compact the dirt when I backfill inorder to pour the 5' by 5' concrete foundation. I am concerned about the dirt settling over time and ruining the concrete. Thanks.

  2. #2
    Join Date
    Jun 2004
    Location
    Chicago, IL
    Posts
    737

    Default Re: dirt compacting

    Why not just jet it?

    Backfill and then the next day take a piece of 1/2" copper about 8ft long, solder on a fitting to male thread (that fits garden hoses...sorry I dont remember what size, but any hardware store has a garden hose and copper fittings).
    Then hook that sucker up to a garden hose and stick it in the ground. Ease it in as you soak the ground and before you know it will saturate the soil and that'll help it settle.
    We've had no rain around here and I've had to do that to get our backfill to settle for final grading. Thats the only way I really know how to do it.

    -J
    -----------------------------------------------------
    "Anyone who has never made a mistake has never tried anything new." -Albert Einstein
    Cluelessness: There are no stupid questions, but there are a LOT of inquisitive idiots.

  3. #3
    Join Date
    Jun 2004
    Location
    Chicago, IL
    Posts
    737

    Default Re: dirt compacting

    Is this foundation on top of the excavation? Or in the excvation.. I was a little unclear about that... if it is above and you're really worried... I'd jet it and then fill in the little bit you have settle, compact with the machine & then place your gravel, compact & pour. Talk to your concrete guy, maybe adding some welded wire mesh might be in order to help strengthen the slab?
    -J
    -----------------------------------------------------
    "Anyone who has never made a mistake has never tried anything new." -Albert Einstein
    Cluelessness: There are no stupid questions, but there are a LOT of inquisitive idiots.

  4. #4
    Join Date
    Jul 2005
    Location
    ND
    Posts
    18

    Default Re: dirt compacting

    Thank you much for the help. It is ontop of the excavation. I would drive the machine over it to compact it but I forgot to state that there will not be enough clearance on about half of the hole to allow me to do that. It is very close to a row of trees so I will have limited space inorder to compact. What is your professional opinion know? As always thanks.

  5. #5
    Join Date
    Jun 2004
    Location
    Chicago, IL
    Posts
    737

    Default Re: dirt compacting

    Well I would think even after jetting it and letting it settle for a day or two you still wouldn't have very much settlement. You could always just fill that with gravel...and if you want to be real picky get a compactor to compact the gravel before the pour.
    I think its really overkill for such a small slab. Gravel & reinforcement should be just fine. Again, talk to your concrete sub for his professional opinion...hes seen more concrete than most of us.
    -J
    -----------------------------------------------------
    "Anyone who has never made a mistake has never tried anything new." -Albert Einstein
    Cluelessness: There are no stupid questions, but there are a LOT of inquisitive idiots.

  6. #6
    Join Date
    Jul 2005
    Location
    ND
    Posts
    18

    Default Re: dirt compacting

    God bless and thanks alot for your generous help. MIKE

  7. #7
    Join Date
    Mar 2005
    Location
    West Palm Beach, FL
    Posts
    98

    Default Re: dirt compacting

    I hope you have enough room to obtain the proper angles of repose or do the proper shoring on a hole this deep, if someone is going to be working down there. If the hole's sides are sloped properly for safe working, backfilling with the excavated dirt is probably the best option, compacting in lifts sized to the compactor you are using. If you go with a shored hole, the gravel is a good option, or use the dirt and a jumping jack compactor like this: http://www.sunbeltrentals.com/catalo...p?id=5&sid1=28 .
    Be careful!
    Ted

  8. #8
    Join Date
    Jun 2004
    Location
    Chicago, IL
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    737

    Default Re: dirt compacting

    Excellent reminder on the above post... if you're doing a dig that narrow & so deep you need to make sure you have adequate shoring/bracing to prevent injury. I always take the day off (sort-of to help my sewer-water guy do the hookups on each home, theres something fun about playing in the dirt once every couple months!) Either way... we probably only need a 4-5' trench to get things in, but usually we end up with a 12-13' trench about 8-9' deep, and we watch it like crazy. Somone died locally on a commercial school project in my town, doing sewer/water work only 7' down. They were trapped and he was already gone by the time the firefighters got him out. I'd recommend talking to someone...or an excavator about the best way to proceed.
    -J
    -----------------------------------------------------
    "Anyone who has never made a mistake has never tried anything new." -Albert Einstein
    Cluelessness: There are no stupid questions, but there are a LOT of inquisitive idiots.

  9. #9
    Join Date
    Jul 2005
    Location
    ND
    Posts
    18

    Default Re: dirt compacting

    Thanks for the replies. It's not as if I am totally inexperiences in these materials and techniques. I made a 30' by 30' by 6' deep hole with a bobcat in my backyard for a pond. It has a sidewalk around it and sense the ground was sloping alot on the rear end it has a waterfall there.

    There are good reasons to do it myself not just to save money but just for the good knowledge I learn from it and also the fact that I had a hydrant (located in a barn) that wasn't working so I called the local guy who works on them to come out and fix it so he purposes a 2,000 dollar fix because he has dig down and replace all the parts. I investigated and it turned out a simple 0 ring had just worn out of which only costs about 2 dollars at the local true value. I really don't feel like calling him up anymore. Either he is incompetant or greedy. The latter is probably the most plausible choose.

    I have modified somethings but if you wanna read a general step by step procedure of what I am planning to do then you can read on. Please criticize and give pointers if you don't mind. The horse water needs to be connected to an existing 3/4" galvanized steel pipe waterline that is 7' below ground. I live in an area that has a 6' frostline. After I call and have someone out to locate where the lines are located I was going to dig down 8' deep with a backhoe and and insert a framed plywood box to prevent the sides from caving in. The plywood box would have 3/4" plywood on the outside and 2 by 6's on the inside. It wouldn't be framed like a house wall with the 2 by 6's going up and down but instead the 2 by 6's would be going left and right and be dadoed on there ends where they would fit together. The 2 by 6's would be space at 12" o.c.. So sense the box is 8' long I would need 9 of them. I need this box for something else so the extra expense of the materials wouldn't be anything to me. The inside length and width of the box would by atleast 4' by 4' to allow me enough room to work. After I set the box inside the hole and climbed in it I also need to make another hole on the bottom of the hole that has a 14" diameter and is 2-3' deep for a 12" id pvc pipe. I'd probably just make this hole with a post hole digger since it isn't that deep. Then I'd make a hole in the plywood box so that I can get to the 3/4" galvanized steel pipe and tap into it and run it in and up the box to 3' above ground level.

    Sorry for the long post but please read on if you don't mind. Next goes in the very long 12" id pvc pipe that will be 13'-14' long. This measurement adds up because 8' is for the hole, 2-3' is for that extra 14" diameter hole on the bottom, and 3' of it is projecting out of the hole. This pvc pipe is in the ground so far because it serves to keep the 3/4" galvanized pipe from freezing up because the galvanized pipe is in the middle of the pvc pipe and warm air from the bottom of the pvc pipe hole constantly rises preventing the 3/4" pipe from freezing.

    After this I would need to make piers/pillars instead of a slab inorder to support the horse waterer. I was thinking about using 5 by 5 by 8' treated posts with lag screws or 12 by 12 by 8' concrete piers with 3/8" bent threaded rod on top of it. I am mainly concerned about the piers settling over time and running my installation. They don't have to hold that much weight though. There own weight is far more than the horse waterer. I was thinking about compacting the ground where the piers are located with a 1" diameter rod that is 6' long on the bottom of the hole. For the piers I was planning on making a rectangular box out of 1/2" plywood that is 12" by 12" by 8' long. The inside diameters would be 11" by 11" by 8' long. I would then make 4 of these and place them in the hole and position them and hold them with 2 by 4's bracing them and preventing them from shifting while I backfilled.

    When the 4 plywood rectangular boxes for the piers are checked in place and level I would then remove the outer box that is preventing all the dirt from caving in. I probably will make this box in sections to make it easier to remove or perhaps I will just hook it up to the backhoe with a chain and lift it out. If all goes well here I backfill the dirt evenly to try and not disturb the 4 plywood boxes. Next I would pour the concrete in the 4 rectangular boxes and provide 3 1/2" diameter rebar rods at 8' long in each of them (12 total) to try and strengthen the concrete piers. I'd also remember to place and sink the 3/8" bent threaded rods into the concrete inorder to provide the attachment for the horse waterer. Next I would place the horse waterer ontop of the piers and bolt it down. Finally I'd connect the waterline and electrical to the waterer.

    Does this installation sound exceptable?????. Please help and give suggestions if you don't mind. Thanks alot for the good help as always.

  10. #10
    Join Date
    Mar 2005
    Location
    West Palm Beach, FL
    Posts
    98

    Default Re: dirt compacting

    Sounds like a whole lot of work for horses and frost. I would think you could have the nags sipping frosty Perrier for a couple years before you got a return on this investment (joke?).

    The first problem I see involves finding a machine/operator that can dig a hole that small, that deep, other than someone with a big auger. The next problem is stripping the forms from your piers after your ditch shoring is removed, you would still need to get in the hole (not me!).

    I think I would build the shoring, do the pipe, remove the shoring (all as you described),fill the hole to the frost line with gravel and the rest of the way up with concrete, no forms except at the top to create the shape, and rebar to taste. A 4 x 4 x 7' hole would take about 4 cu. yds, figure 6 or 7 knowing you can't get the hole that precise. Thats about $700 homeowner bucks worth of concrete in my neighborhood and a whole lot less work. Of course, my work is usually in the swamps, not much frost to deal with here.
    Ted

  11. #11
    Join Date
    Jul 2005
    Location
    ND
    Posts
    18

    Default Re: dirt compacting

    Thanks for the reply. Very helpful. I don't know whether or not it is an exceptable practice but I was just going to leave the ply shoring for the piers in there after I backfilled. I know that the ply would eventually rot but I don't see why it would matter to much sense it is only on the sides and not underneath it. I just figured while it rotted dirt would just get replaced with it. Mayby I should just use 5 by 5 treated posts for the piers. I like the concrete better because of its strength and it lasts much longer (more reliable) than the wood alternative. As always thanks for your help and keep it coming if you don't mind:).

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