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Backfilling saturated soil

Backfilling saturated soil

Backfilling saturated soil

(OP)
We have an open excavation (50' x 25') that needs to be backfilled.  It has filled up with rain water so the soil is generally saturated.  We can pump out most of the water but is there a concern for for the satuarated soil?  Eventually there will be a structure in the area but we don't anticipate being ready for foundations for another year.  The area would be re-excavated at the time.
The excavation is 6-9' deep.

RE: Backfilling saturated soil

Well, what kind of soil is it?  Do you know how much is saturated  - 6 inches or 5 feet?

RE: Backfilling saturated soil

(OP)
Generally sandy with some fill material.  I am using the term saturated but it is really just wet at the surface (as far as I can tell).  It seems that after a few days of dry weather it dries almost completely.

RE: Backfilling saturated soil

IMHO, overexcavate one foot, pump out the standing water, and backfill / compact per specification. Maintain dewatering around the clock until backfill is complete.

www.SlideRuleEra.net idea

RE: Backfilling saturated soil

Well, if you can get it to dry, I would do that, and rework the top foot by scarifying, moisture conditioning and recompacting at project specs.  I am not sure that you need to "excavate" 1 foot as SRE indicates, but it is definately more conservative (as in: not a bad idea). At a minimum, once it has dryed and is stable on the surface, cut in a ramp, and get some trucks in to do a proofroll.

The main thing is to get it stable and keep it dry. Having a slight slope to the subgrade / backfill, down to a pump is a good way to maintain this.

The contractor should protect his work.  Obviously, this can be difficult with a big hole; therefore, there is no reason that you should not be able to ask the contractor to show the work completed / subgrade is suitable for placement of more fill.

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