Trench Compaction

[tkoden]

I need to put in 2300' of 2" IPS HDPE and 14-2 direct burial wire 2' and 1.5' deep respectivly. I would prefer to use a cable plow but no one around here rents them for that small of a project. So, I have to use my trencher. My issue is the trench goes down the middle of a step road so it needs to be compacted really well. I saw 4" x 42" diameter compaction wheels for skid steers and excavator but they are pricey and will kill most of my profit.

Does anyone have any cleaver ideas for compacting the trench?

 

[buckfever]

Do you have access to a mini. Excavator?

Fab up a compaction wheel that mounts to the bucket. A two foot diameter wheel would be enough to compact your first lift after bedding the pipe and putting 6" of dirt on top. This way you use one machine to trench and the other to pack and back fill with.

 

[tkoden]

I have a Tak 290 20k lb excavator. I can get a used wheel for the excavator for $1600.

 

[Landworks]

Dig with the trencher and backfill with 1/2 inch limestone ? I come up with about 47 tons of rock per trench. For the trouble of dealing with the soil and headaches later on with not meeting compaction, maybe this would be a better option. We often use a limestone here called 9m (Kentucky) that will be at compaction when it falls in the trench.

 

[CM1995]

Stone backfill works well - fast and easy but if it's on a steep drive (I assume not paved or not going to be paved?) then the onsite material is the best choice compacted in lifts to prevent a washout.

You could rent a jumping jack with a narrow foot but by the time you include rental and labor I'd bet you could buy the compaction wheel and have it for future jobs for the same cost.

 

[buckfever]

Im with cm, buy the compaction wheel and be done with it.

 

[jprefect]

use a jumping jack. back fill with sand stone what ever then run down the trench.

 

[CM1995]

use a jumping jack. back fill with sand stone what ever then run down the trench.

That's 2300' of trench to compact with a jumping jack, 2' deep..

 

[Melness64]

If your worried about compaction ,jumping jack all day long ..150mm layers 7/9 passes per layer (that's the way things are done here in Scottish Highlands )job done .

End of the day the compaction you get depends solely on the material you use and what you use to compact material .Sealing the the top of the track is key IMO to prevent washout as others have already said .

 

[CM1995]

If your worried about compaction ,jumping jack all day long ..150mm layers 7/9 passes per layer (that's the way things are done here in Scottish Highlands )job done .

End of the day the compaction you get depends solely on the material you use and what you use to compact material .Sealing the the top of the track is key IMO to prevent washout as others have already said .

Welcome to the Forums Melness64!:drinkup

Curious as to what it would cost labor and equipment in Scottland to backfill the trench using a jumping jack? Say 7 passes per layer, 4 layers so that's 28 passes total at 2300' long each pass, which is roughly 12 miles of running a jumping jack.

I know my costs and I could easily buy the compaction wheel for $1600 just in labor savings and the time would be much quicker obviously. Labor, material and equipment costs vary greatly so just interested to see how other contractors go about it.

 

[td25c]

Dig with the trencher and backfill with 1/2 inch limestone ? I come up with about 47 tons of rock per trench. For the trouble of dealing with the soil and headaches later on with not meeting compaction, maybe this would be a better option. We often use a limestone here called 9m (Kentucky) that will be at compaction when it falls in the trench.

That's more than likely how we would approach it in a road bed . Fill trench with stone & compact with a Ford 4000 farm tractor .

On steep hills I would drop in sand bags say every 30 to 50 feet to help prevent washing out .

 

[buckfever]

With you a 100% cm. If you buy the compaction wheel you will have something for the next job. Using a jumping jack all you will end up with is a worn out jumping jack and a miserable laborer at the end of the job.

 

[Melness64]

Do you guys over the pond not have random compaction tests by the highway authorities . Over the 30 odd yrs i've been involved in open trench operations in the mains renewal gas industry ,i've dug/backfilled miles and miles of it . Typical system for us is

Dig track

Blind gas main with dirty sand as we call it

150mm 0f fill ..compact ..marking tape.. 150mm layer ..compact and so on .

All done with wacker/jumping jack sometimes 3 of them at same time . Never had any problems with worn out wackers (always properly maintained )Obviously the bigger the main the bigger the trench the bigger compactor . Final layer is tested with a CLEGG IMPACT SOIL TESTER . If my memory serves right ,we aimed for 25% to 31% on main roads ,19% to 21% on footpaths .Company had about 40 to 50 4 man squads for mains work and 20 od 2 man squads for private and industrial service work .Just a little insite just incase you guys think i'm blowing wind up your asses . Kinda miss working in the streets .


We have used compaction wheels on bobcats ,but with the amount of street furniture it isn't always viable to use . Plus our climate and ground conditions don't suit plant that uses high vibrations to get the compaction because of the high moisture content in the asdug it just causes problems hence why we tend to use whackers because of their lower frequency vibrations.





Here's a link to what we have to adhere to. Company i worked for worked to the letter .... https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/11042/sroh.pdf

 

[Melness64]

With you a 100% cm. If you buy the compaction wheel you will have something for the next job. Using a jumping jack all you will end up with is a worn out jumping jack and a miserable laborer at the end of the job.

If jumping jack is setup properly ...a child could use it .

 

[d4c24a]

If jumping jack is setup properly ...a child could use it .

They don't do things over the pond like we do , mind we use foam a lot now which stops the need for compaction

 

[Landworks]

We have also backfilled w 9m limestone and then sprayed some asphalt emulsion on top of the trench to alleviate washouts. Its essentially the same as a chip and seal surface at that point. They must have some willing labor across the pond because I would go through 15 workers before I got 12 miles compacted with a jumping jack.

 

[CM1995]

Do you guys over the pond not have random compaction tests by the highway authorities .

Of course we do but the testing companies are all private in our area. The DOT does have their own techs for some road work but the few DOT projects I've been involved in they allowed us to use a private company. This was just turn lanes and curb cuts.

Usual spec's for roads and parking lots are 95% density and 98% for building pads using a nuke gauge.

I have a small crew of 4 men with me being the 4th. My method of thinking is if I can pay for an attachment in a job that reduces labor, then it's a smart move. I wouldn't ask my operators to backfill a trench with jumping jacks and I don't want to deal with day labor..

As Scrub says "Different strokes".

 

[td25c]

Do you guys over the pond not have random compaction tests by the highway authorities .

Yeah , that would depend on what type of road . Big difference in a paved state highway and an unpaved county / township road .

The way tkoden is describing the job possibly using a cable plow or trencher I'm guessing this is an unpaved county road .

In my area the county relies on truck & equipment traffic for the compaction test . If the road fails you call the county highway department office & say .... " Hey Joe , Need some more stone trucks and a grader at such & such " . Joe then takes care of it when time allows .

 

[Fatgraderman]

Do you have access to a grader or willing to hire one? Here on pipelines we articulate and run the front wheels to compact over the lines (fairly narrow trench). If it's clay and not all the dirt has fit in the excavation then we put the back tires on. 2600 feet is half a mile- shouldn't take long to go back and forth a few times.

 

[Melness64]

They don't do things over the pond like we do , mind we use foam a lot now which stops the need for compaction

Been using foam concrete since the early nineties.