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hack of all trades
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Discussion Starter · #1 ·
I have a short retaining wall that I built beside a shallow footing so that I could dig out my crawl to a reasonable depth.

Backfilling and compacting (by hand), I started to notice the vibration disturbing the shallow stone footing that I'm trying to stabilize/preserve.

Any tips on how to compress this soil without too much vibration? I plan to top this knee wall off with some crushed stone and 4+" concrete.

I assume the answer will be "excavate the original foundation and rebuild it with a footing to proper depth". I was tempted to do that but this is work I'm doing in my own house and I need to stop adding projects so I can get back to paying jobs.
 

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Use lean concrete to fill the void instead of soil. They will batch a 1 bag mix that is like a 500 psi mix. They can make it flowable soit fills all voids. It is used a lot for utility trenches under streets.
 

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hack of all trades
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Discussion Starter · #7 ·
I need to order 3+ yards of concrete for the slab so i guess i can get enough to backfill that area. The situation is not ideal but i need to find a reasonable compromise.
 

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hack of all trades
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Discussion Starter · #10 ·
dayexco said:
personally, i wouldn't dump three yds of concrete in there. some poor bastard will have to hammer that out someday. i'd go with the pea rock.
The 3 yards is for the small slab over that crushed stone (with vapor barrier between) ...but I did planning on pouring a slab over my compacted backfill behind retaining wall to seal it up.

I definitely think that same way though "what happens when some poor bastard needs to change something here..."
 

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Did you mention what you were backfilling with? Its looks like gravel. If I'm not mistaken, you can achieve 95% compaction just with placing the clean stone, no compaction needed. Presto, problem solved.
 

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hack of all trades
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Discussion Starter · #12 ·
cdkyle said:
Did you mention what you were backfilling with? Its looks like gravel. If I'm not mistaken, you can achieve 95% compaction just with placing the clean stone, no compaction needed. Presto, problem solved.
I have #7 crushed stone a few inches deep across the whole space but I didn't order enough to backfill the entire trough. I used the clean fill that I dug out of the crawlspace to backfill. The soils here are heavy on the clay so it's mostly clay.

I wish I didn't have to backfill so much but I needed to leave myself space to lay the block while still getting close to the shallow stone footings.
 

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Just fill the space with stone, and when you do the slab, let the concrete pour down into those empty cells and fill that wall.

If you have footing movement of the existing now, you may need the extra strength of a solid wall. Reviewing the photos, it "looks" like you may have undermined the existing foundation.

Get that thing buttoned up before you have some issues.
 

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Chuck
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Use lean concrete to fill the void instead of soil. They will batch a 1 bag mix that is like a 500 psi mix. They can make it flowable soit fills all voids. It is used a lot for utility trenches under streets.
Here we use "CDF" Controlled density fill which is like lean concrete with no stone. The best part is it will flow, you don't need to compact and you can dig it with a shovel.
 

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Love me some Concrete
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Very glad to see you slugged the block work! Very nice.

I would also just gravel it. You could pin the top when you do the top slab to keep it from dropping even if the ground settled a bit. With it being interior I would not do that if frost heave was an issue but interior you should not get frost heave.

Or just put in the dirt, put down 2" foam over the dirt and pour your slab pinned to the wall on the slugged walls. I would add a few more slugged wall for the support though.
 
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