# Solutions to soft ground under parking lot?



## mattg2448 (Jan 26, 2015)

So I am under the gun to get our job done that I have been posting about earlier in the picture section. We are almost ready to stone the parking lot and the ground is super saturated. Our dozer is even leaving 6" ruts. We need as much material possible to build up elevation to subgrade so I wouldn't want to under cut if I don't have to. What are my next solutions? It's all dense sand with very little clay in it but seems to hold water pretty good.


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## dayexco (Mar 4, 2006)

i'd request a change order and have them design a tile system for the lot, to me sounds like out here, we'd request/place fabric before the base course.

did the soil boring logs in the bid form show any of this up front?


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## mattg2448 (Jan 26, 2015)

There were no bore logs. It was a pretty bare bones project. Private owners trying to save cash.


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## mattg2448 (Jan 26, 2015)

It is T&M but I still want to work within a reasonable range.


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## dayexco (Mar 4, 2006)

you need a CE/PE involved immediately...you need HIM..or her...to tell you how to proceed. 

you can recommend, but should things go south, it'll all be laid back in your lap.

be a nice guy, but i've been in these scenarios...DO NOT PROCEED without a stamped set of plans....and what you'll be paid for it.

seen waaaaaaaaaaay too many times a contractor gets too much time and material stuck into a job and not get paid trying to be a nice guy.

good luck


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## mrcharles (Sep 27, 2011)

I agree with Dayexco..... This needs to be engineered. If the soil fails the structure will fail. 

That being said Lime stabilization sounds like it might be a good solution.


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## rustyjames (Aug 28, 2008)

I also think the lime treatment would be an option. Flyash is another but probably won't be allowed due to to environmental concerns.


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## dayexco (Mar 4, 2006)

You guys ever use fabric? 

Why waste your time mixing lime into your soils when you can do fabric for about 90 cents a square yard and be done with it? 

Sent from my SCH-I545 using Tapatalk


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## Moxley-Kidwell (Jan 28, 2011)

I agree with Day we'll use non-woven under stone, but if you can't get a dozer across it you've got bigger problems than fabric will fix. Either undercut and fill with stone on fabric, don't know could be feet though or someone may have to figure out a drainage system.

We've used pelletized lime with good results but it's super expensive so probably not a good solution. Soil cement? Only other solution i have is good weather, time and a lot of tooth up the area, let it dry some, do it again, again, etc.


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## JDavis21835 (Feb 27, 2009)

Being the soils are sand, portland cement would provide the most effective results in a stabilization situation. Realistically, stating its sand, and rutting, I'm guessing the silt content is high, plus high moisture content. Drainage provided through a series of 4 inch tile and stone, which will require it being wrapped in a filter fabric burrito in that sand, and then fabric and stone across the entire parking area to bridge it. I would personally recommend 3 inch and then choke it off with a 21a. That said, it would be my recommendation, but I'm no soils engineer, so I cannot provide any promises that it will work 100% for the situation


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## dayexco (Mar 4, 2006)

jdavis, what is 21a?


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## JDavis21835 (Feb 27, 2009)

dayexco said:


> jdavis, what is 21a?


21A is michigans name for road base, 3/4-1inch crushed with fines. 
Similar to Ohio's road stone, they call it 304


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## dayexco (Mar 4, 2006)

JDavis21835 said:


> 21A is michigans name for road base, 3/4-1inch crushed with fines.
> Similar to Ohio's road stone, they call it 304


that's what we call "class 5"


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## JDavis21835 (Feb 27, 2009)

dayexco said:


> that's what we call "class 5"


The only class materials I am used to is sand in Michigan. Almost everything backfill wise was class 2 sand. A rather coarse sand, with natural aggregates in the mix. Optimum moisture content would be 8-11% depending on grain size. If you had a good draining site, You could just pour the water to the sand and get compaction without doing anything else


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## mattg2448 (Jan 26, 2015)

Cut a 10" lift in half and ran 5" of 1x3ish material and laid fines on top, then 21a, that place is like concrete now. Subgrade was nasty.


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## jhark123 (Aug 26, 2008)

mattg2448 said:


> Cut a 10" lift in half and ran 5" of 1x3ish material and laid fines on top, then 21a, that place is like concrete now. Subgrade was nasty.


Did you use fabric?


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## Petert0204 (Apr 25, 2016)

We're glad it will help!


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## PAS INC (Apr 24, 2016)

dayexco said:


> You guys ever use fabric?
> 
> Why waste your time mixing lime into your soils when you can do fabric for about 90 cents a square yard and be done with it?
> 
> Sent from my SCH-I545 using Tapatalk


We use marafi paper (fabric) under any parking area or roadway we do, It stabilizes and keeps your material from mucking into the ground.


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