Retaining Wall Sinkage

Discussion in 'Hardscaping' started by Bleed Green, Aug 27, 2009.

  1. Bleed Green

    Bleed Green LawnSite Bronze Member
    Posts: 1,514

    The ground behind the retaining wall in my front yard is sinking and I am not sure how to remedy it. I have tried filling it three different times and it just keeps sinking out. I am not sure why it is doing this. When the company installed the wall they did have to move it back a little bit because they put it in the wrong place. I am wondering if having to move the wall had something to do with it sinking out like it is. What would you guys suggest I do to try to fill it and get it to stay solid behind the wall?
    Thanks in advance.
     
  2. Summit L & D

    Summit L & D LawnSite Senior Member
    Posts: 269

    Pictures, please.
     
  3. Bleed Green

    Bleed Green LawnSite Bronze Member
    Posts: 1,514

    what is the easiest way to go about posting a picture?
     
  4. tthomass

    tthomass LawnSite Gold Member
    from N. VA
    Posts: 3,497

    Save it to your computer, click on "post reply" and click one "manage attachments"
     
  5. DVS Hardscaper

    DVS Hardscaper LawnSite Fanatic
    Posts: 6,412

    Respectfully, I don't think a picture is needed.

    The ground has settled / sunk for one of two reasons:

    a) The area that sunk was disturbed and/or imported and not compacted.

    b) Water is somehow collecting behind the wall. Could be surface water. Could be the downspouts on the house are discharging water thats finding it's way behind the wall. Could be a leaking water main.


    It's one of these two scenerios. Water or uncompacted soils.

    I'll go as far to say it's most likey uncompacted soil.




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  6. andyslawncare

    andyslawncare LawnSite Senior Member
    Posts: 812

    Does your wall have drainage behind it? How tall is the wall? What did they use for the base and how deep was the base? Pictures would be helpful. Sounds like they didn't install drainage, didn't make the base deep enough or didn't use the right material, or didn't compact the soil good enough.
     
  7. Bleed Green

    Bleed Green LawnSite Bronze Member
    Posts: 1,514

    There is a storm sewer line that runs under where part of the wall is. There is some mud in the pipe now that I look at it again. Maybe the pipe has a fracture in it and the mud is sinking down into the pipe? I wouldn't think that would be causing it to sink all the way along the wall though like it is.
    If there is a broken pipe below where the wall is, what is the best way to fix it? just dig down, patch the pipe and then rebackfill the wall i guess?
     
  8. DVS Hardscaper

    DVS Hardscaper LawnSite Fanatic
    Posts: 6,412

    Improper drainage would cause a wall to blow out.
     
  9. Bleed Green

    Bleed Green LawnSite Bronze Member
    Posts: 1,514

    I was thinking when they had to move the wall back a foot or so they got off the footing and were pissed that they had to move the whole wall anyway, so they didn't care and now the weight and the everything was making the wall settle. I could be wrong, just a theory.
     
  10. DVS Hardscaper

    DVS Hardscaper LawnSite Fanatic
    Posts: 6,412


    I still think your problem is derived from improper / lack of compaction. If a line is leaking, you have to dig around it, find the leak, and repair.

    In our area there is a big, new retaining wall in a new housing development. Built by a multi-million dollar company that mose nothing but big, monster walls. Well a water main that feeds the community sprung a leak and caused the wall to fail. Not sure why, but the developer is trying to get the wall contractor to accept responsibility.



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