# Backfill compaction



## NewSchool (Jan 8, 2012)

We are replacing a bunch of old 8" clay under an apartment complex parking lot. What methods do you use to properly compact the backfill?


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## Local 9 Plumber (Apr 20, 2012)

NewSchool said:


> We are replacing a bunch of old 8" clay under an apartment complex parking lot. What methods do you use to properly compact the backfill?


I used a jumping jack. Good times....Not!


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## cbeck (Mar 7, 2012)

^^what he said, man those things will make your hands go to seep and numb!! I swear those things are the reason I had carpel tunnel surgery!


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## Widdershins (Feb 5, 2011)

cbeck said:


> ^^what he said, man those things will make your hands go to seep and numb!! I swear those things are the reason I had carpel tunnel surgery!


I had one get away from me in a 6' crawlspace one time. Broke my ankle and cracked a few ribs.


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## bulldozer (Jan 11, 2009)

Pipe burst the main no compaction needed. Or backfill with flowable fill


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## NewSchool (Jan 8, 2012)

Can you get 100% of the dirt back in using a jumping jack?


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## AlbacoreShuffle (Aug 28, 2011)

NewSchool said:


> Can you get 100% of the dirt back in using a jumping jack?


Close enough.
Don't try and fill the trench to the top and then compact.
Do it 12" at a time.


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## TX MECH PLUMBER (May 27, 2011)

What he said. And water. U need water. Will ther be compaction test?? What kind if soil??


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## RealLivePlumber (Jun 22, 2008)

NewSchool said:


> Can you get 100% of the dirt back in using a jumping jack?


Depends on the lunar cycle.


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## justme (Jul 4, 2012)

Flowable fill is another way to backfill .


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## ILPlumber (Jun 17, 2008)

Pea gravel is nice. It's compacted pretty well as soon as it lands in the trench.......

Ag lime works well for the price. 

Otherwise, chase that jumping jack around...............


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## RealLivePlumber (Jun 22, 2008)

I tell the young uns it's like dancing with a big girl who likes to lead.....


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## deerslayer (Mar 29, 2012)

We usually put grits or pea gravel around the pipe and tamp the dirt in with the hoe and lots of water. If compaction is critical pea gravel the pipe and use CDF or flowable fill and you can be sure there will be no settling.


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## OldSchool (Jan 30, 2010)

deerslayer said:


> We usually put grits or pea gravel around the pipe and tamp the dirt in with the hoe and lots of water. If compaction is critical pea gravel the pipe and use CDF or flowable fill and you can be sure there will be no settling.


We use a hoe and a pogo stick ... I got to find a cheaper way to do this as the hoe is charging to much


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## Adamche (Feb 10, 2012)

Vibrating plate, water, 1' at a time, easier to handle than a jumping jack( we call them a Wacker)


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## smoldrn (Oct 4, 2010)

Adamche said:


> Vibrating plate, water, 1' at a time, easier to handle than a jumping jack( we call them a Wacker)


We've always called them a whacker packer.


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## TX MECH PLUMBER (May 27, 2011)

Whacker packer is a brand But that what we call them too. Unless we use a vibor plate.


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## dayexco (Oct 12, 2009)

depends on your soil types. on granular material, a vibe plate works the best, because it shakes the particles together, eliminating any voids. on a cohesive (clay) soil...you either have to knead it together (sheeps foot), or use impact (jumping jack). vibration will work, but not as near as effective on clay type soils. moisture content is critical in soil compaction. moisture works as a lubricant allowing the soil particles to slide together/denser with considerably less effort. too much water, and your cohesive soils turn to bubble gum and nothing gets done, and when the water migrates from the excavation, it will leave a void. good luck


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## Epox (Sep 19, 2010)

Exactly, dirt is cheaper and you won't have to have it hauled away if you reuse it. If possible I have someone running a yard hose as I'm digging to wet the dry soil down as it comes up. By the times I'm ready to refill it has cured and evened out into the soil. A little goes a long way. Like my Dad told me many years ago, "you can't tamp mud". 
Fwiw, our soil is typically dry as a bone, some of you I'm sure don't have to wet it down. You want it to compact in your hand, but again go easy on the water.
Depending on the conditions in the concrete field we estimated 25% extra material when planning to compact.


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## user8031 (Dec 14, 2011)

6" layers, compacted, until 12" above crown of pipe.


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## fresnoplummr (Feb 25, 2011)

OldSchool said:


> We use a hoe and a pogo stick ... I got to find a cheaper way to do this as the hoe is charging to much


If you use the hoe often and leave a tip on the nightstand she'll usually lower her price.....


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## gear junkie (Jun 20, 2008)

On a long straight trench-mini roller
all around use-wackey packer, I prefer 6" lifts
around pipe-sledge hammer

I never compact the top 4" if grass is the top cover. Since this is for a parking lot, maybe some 3/8- would allow for better compaction if original soil isn't great.


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## DesertOkie (Jul 15, 2011)

Slurry. 1 bag of portland in every yard of reject sand.


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## patrick88 (Oct 14, 2008)

fresnoplummr said:


> If you use the hoe often and leave a tip on the nightstand she'll usually lower her price.....


The tip offsets the lower price.


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## Frodo (Mar 12, 2021)

beach sand and a hose will give you 100% compaction
It is all I use anymore on bathroom groups

I still tamp the mains and laterals but a bathroom group that looks like pipe city
SAND


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## ShtRnsdownhill (Jan 13, 2016)

Frodo said:


> beach sand and a hose will give you 100% compaction
> It is all I use anymore on bathroom groups
> 
> I still tamp the mains and laterals but a bathroom group that looks like pipe city
> SAND


luckily on long island all the ground is sand, for the most part.....I usually water all my underground piping if im backfilling...
upstate the ground is hard pan and shale, and LOTS of rocks..any water lines are sleaved and drain lines usually go in a bed of small pea gravel..
PS..your only 9 years late answering this thread...lmao....


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## Frodo (Mar 12, 2021)

I have never used pea gravel. Our ground is pretty much clay and sandy loam

I use a ''sheeps head'' attachment on the back hoe to get compaction. that sucker will shake your liver loose


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## ShtRnsdownhill (Jan 13, 2016)

Frodo said:


> I have never used pea gravel. Our ground is pretty much clay and sandy loam
> 
> I use a ''sheeps head'' attachment on the back hoe to get compaction. that sucker will shake your liver loose


upstate most piping in the ground has to go below frost line or get pushed up over the years, gravel around the pipes helps drain the water away from the pipe so you dont get the freeze thaw cycles to push them up..
I have phone line that cuts across my fields..60 years ago they put it 3 to 4 ft down..now its maybe 6 inches from the surface and I keep hitting it when putting in food plots, so now I have to work around it and have it marked out well...


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## leakfree (Apr 3, 2011)

Any job we did where it was checked by a guy with a machine for compaction he said anything we used had to be compacted in 6" lifts, if we used CA-7 3/4" stone no compaction was required.


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