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12" dual wall tile trenching

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user123

Active Member
Joined
Nov 19, 2015
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25
Location
Midwest USA
Looking to trench in 12" dual wall platic pipe with a 320C at depth of 10 foot. I have a spoon attachment for the bucket that the pipe will properly rest in. My question is what is the best way to maintain grade/slope for the length of 3200 ft? Is there a cheaper option than a fancy gps set up? Possibly just a laser system attached to the stick of the excavator? (That way I dont need a guy in the trench with laser pole checking grade)The reason I ask is I think it would sure be cheaper than having a contractor come in, dig a trench deep and wide enough for a plow to come in with a trench box to lay it. (The soil is heavy clay) Any opinions or ideas what be great.Thanks!
 
Oxbow

Oxbow

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Joined
Nov 22, 2012
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1,220
Location
Idaho
Short of a grade system on the excavator, a pipe laser would work very well. You'll have to bench down or use a trench box, but either way you will have to have labor so grade checking using a pipe laser would be your best solution in my mind.

A formed ditch, such as you would get with your spoon, would have to be perfect in order to support the pipe up to the spring line. Do you have to bed the pipe and compact the backfill? It may be easier to excavate with a conventional bucket, and bed/backfill with sand, pea gravel, or whatever clean (no fines) material that is available.
 
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user123

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Nov 19, 2015
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25
Location
Midwest USA
No I don't believe I need to backfill with any rock. Also that would add more cost to the job having to truck in rock. Although I agree that would be easier than using a spoon on a bucket
 
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Shimmy1

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Aug 14, 2014
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4,333
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North Dakota
How much slope do you have? Minimum for pipe is 0.1%. That translates to a foot in a thousand feet. You're going to want something accurate. Only thing I would use (other than GPS) would be an angle-compensating laser receiver. AND, I would still have the guys laying the pipe using the grade rod to check the pipe after it's laid.
 
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user123

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Nov 19, 2015
Messages
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Location
Midwest USA
This job is for myself. Its a main for farm drainage, I'v actually decided to go with 24" that way it has plenty of capacity for added drainage in the future. I have not laid it yet its going to be a spring project.
 
guisep3

guisep3

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Oct 6, 2013
Messages
140
Location
Pittsburgh, Pa
Just bought myself a Spectra LR60 that comes with a magnetic mount that sticks to the stick of the excavator. It is used in conjuction with any rotating laser. I just installed 4 inch pvc from inlet about 20ft long. Set grade a both ends with the laser and then set the fall or pitch you want or need on the pipe. The LR 60 also comes with a magnetic monitor for the cab that displays the grade your carrying.
 
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Brad SEIN

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Feb 14, 2015
Messages
34
Location
SE Indiana
We have done a lot of these mains. You will have to bench the trench back or use a trench box. You will have to crumb the trench even with a spade tip. Also will have to place and push the pipe together. Depending on the soil at that depth you may want to forget the spade and use a 4' bucket and bed to the top of the pipe with stone.

It typically gets really wet at that depth depending on soil type. If it gets wet and the bottom gets soft, then the sides are going to start pushing in. At this point you will probably lose the support necessary for the pipe, and will need stone. You will have a lot of dirt to move to keep the sides benched back far enough to be safe. It's a hand full to cut a 12' deep trench, benched back 12' on each side of the trench and hold grade at the same time. About the time you think you have it figured out you hit a sand pocket and everything gets ugly in a hurry.

You will be fighting water the entire time trying to get pipe down, together and bedded before it floats on you. I'm not saying it can't be done, but in our experiences it takes a lot of help, and more equipment than you think.
You can email me if you have questions.
 
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user123

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Nov 19, 2015
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Location
Midwest USA
Brad SEIN said:
We have done a lot of these mains. You will have to bench the trench back or use a trench box. You will have to crumb the trench even with a spade tip. Also will have to place and push the pipe together. Depending on the soil at that depth you may want to forget the spade and use a 4' bucket and bed to the top of the pipe with stone.

It typically gets really wet at that depth depending on soil type. If it gets wet and the bottom gets soft, then the sides are going to start pushing in. At this point you will probably lose the support necessary for the pipe, and will need stone. You will have a lot of dirt to move to keep the sides benched back far enough to be safe. It's a hand full to cut a 12' deep trench, benched back 12' on each side of the trench and hold grade at the same time. About the time you think you have it figured out you hit a sand pocket and everything gets ugly in a hurry.

You will be fighting water the entire time trying to get pipe down, together and bedded before it floats on you. I'm not saying it can't be done, but in our experiences it takes a lot of help, and more equipment than you think.
You can email me if you have questions.
Click to expand...

Glad to hear from someone who has done this before. Yes it looks like I will need to bed in stone. Do I dig a couple inches below grade, fill with the required amount of stone then grade it to maintain slope?
 
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Brad SEIN

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Feb 14, 2015
Messages
34
Location
SE Indiana
If the bottom goes away then yes you will have to overdig and place stone to grade. I can't emphasize how much more work it is at that depth. You will need a second excavator just to get stone into the trench and backfill. With it benched back you wont be able to reach it with anything else, including the 320 you are digging with. Have you considered hiring a wheel machine for the trench. You have the excavator to dig the bench. You will actually be digging less dirt cutting the bench than you would the full trench. You would have to find someone set up to cut a trench for 24", but they are out there. Could likely eliminate most of your stone, although you may still want to bed to cover the pipe and protect it.
 
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RedlineDrainage

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Mar 14, 2010
Messages
32
Location
NY
Occupation
drainage contractor
We run the Idigbest system, uses a laser catcher but also has sensors on the machine. You can be on grade no matter where the bucket is, very accurate. Do you have a picture of your spoon attachment
 
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