Soil Testing for Conduit Installation

[reslife]

Hello all,

I am collecting requirements for a customer for a small project, and I am hoping someone here might be able to provide some insight.

Basically, power conduit needs to be installed in the ground at a site at a depth of 2 feet that connects a communication shelter to a building (this isn't a major construction project). I need to specify a requirement for 'proving' the soil after the trench is filled. I've seen ASTM D-1557 thrown around on the forums, but I'm not sure that's what I need (seems overkill for the scope of work).

-How do I determine what requirement the site needs for 'proving' the soil after the conduit is installed and the trench filled?

-Mayhap the customer is underestimating the amount of testing required, but I think he's just looking for something that can be done in the field right after filling to get a pass/fail. Is this an unreasonable expectation?

Thanks for any input!

 

[cvg]

just installing a conduit in a small trench, not a big deal. but if you are planning to build something over the top later, than you should require compaction suitable for the future use. D1557 is modified proctor and seems to be overkill. Observation of the compaction using proper addition of water to the soil if necessary and using a "whacker" would probably be sufficient without any proctors being run.

 

[oldestguy]

It depends on what the area is like. If there is foot traffic or animals, you need to be fussy.

Another thought is say "put the soil back at the density it had before installation. Requires in-place density tests or a similar method. No lab tests needed.

Careful if you are using rod probes over electric lines.

 

[Ron]

oldestguy is right...put it back as found. Determine the density of the surrounding soil (in-place), then compact the trench backfill to achieve at least that density. ASTM D1557 (Modified Proctor) establishes a laboratory density to achieve a compaction comparative. All you're doing with the existing soil is letting that become your Proctor.

 

[Ron]

ps...the procedure outlined by cvg will probably do exactly that!