How can I solidify excessively wet soils?
How can I solidify excessively wet soils?
(OP)
We have an earthwork dilemma at a 13 acre site in NJ that is jeapordizing both the cost and schedule of a school addition. The onsite soil, slated for cut to fill, is unsuitable as controlled compacted fill for use under roads, parking lots, etc because it is too wet and will not reach 95% compaction densities. Is there anything that can be done that will allow us to use this soil besides importing clean dry fill, which will be costly, or spreading the wet soil in 1' lifts and waiting for it to dry, which is taking too long and delaying the project?





RE: How can I solidify excessively wet soils?
if they are just wet, drying is cheaper than importing. The soils can be excavated and spread over a predetermined area. Provided there is plenty of hot sun, the material can then be disked to futher promote quick drying. I've done this on several projects and it works quite well.
KRS Services
www.krs-services.com
RE: How can I solidify excessively wet soils?
RE: How can I solidify excessively wet soils?
Yes, I should have clarified that my post related to clayey soils.
KRS Services
www.krs-services.com
RE: How can I solidify excessively wet soils?
RE: How can I solidify excessively wet soils?
But lime, Portland cement and flue dust all will require mechanical mixing - which is no easy feat on a very wet soil...and site.
Please see FAQ731-376 for great suggestions on how to make the best use of Eng-Tips Fora. See FAQ158-922 for recommendations regarding the question, "How Do You Evaluate Fill Settlement Beneath Structures?"
RE: How can I solidify excessively wet soils?
RE: How can I solidify excessively wet soils?
RE: How can I solidify excessively wet soils?
RE: How can I solidify excessively wet soils?
Portland cement is a less expensive alternative, but is much less effective. After all, Portland cement is only 30% lime - and 70% clay (pozzolans)! It will work well in low plasticity clays and very silty soils, though.
Fly ash/flue dust work best in sandy silts/silty sands and some clayey sands.
Tarps might be useful in preventing additional rainfall penetration - but be sure that the rain doesn't drain into your "dry" patch!
Please see FAQ731-376 for great suggestions on how to make the best use of Eng-Tips Fora. See FAQ158-922 for recommendations regarding the question, "How Do You Evaluate Fill Settlement Beneath Structures?"
RE: How can I solidify excessively wet soils?
RE: How can I solidify excessively wet soils?
Are there any particular risks to the machine operators etc?I understand the material used is effectively pure 'quicklime'.
RE: How can I solidify excessively wet soils?
I have written a presentation in microsoft powerpoint on how this all works, and will send you a copy if you are interested, but I will probably have to generate this as a .pdf due to its size, sorry but the animation wont work. (contact me at ian@geotechnical.co.uk)
As to the effect of the lime clouds, this is a VERY serious issue, yes it is normally quicklime that is used, as this is the most reactive, and you should assess all the risks involved with this. Suitable protective clothing, such as masks, goggles and gloves should all be available.
Approaching people from agriculture to help is a very sensible solution, in the UK we have found that there is some cross-over between the two sectors, and often they have plant and equipment which although designed for farming, works very well on construction sites.
There is also specialist plant availble which rotovates, mixes and blends the lime within a hopper to prevent problems with lime dust, and this also includes much smaller plant suitable for single track roads. Whether or not this currently available to you, unfortunatley I cannot comment, wrong side of the world sorry.
If you wont to have a look at some of the kit available, companies in the UK who specialise in this are people like Powerbetter, Con-form, Beaches, Geo-firma, Stabilised Pavments, O'keefe Soil remidiation etc... all have their own web-sites.
RE: How can I solidify excessively wet soils?
RE: How can I solidify excessively wet soils?
RE: How can I solidify excessively wet soils?
RE: How can I solidify excessively wet soils?
I've run across this issue in the environmental field - a large amount of imported clean fill was too fine-grained. Rather than hold up the project to dispute the specs on our fill and wait for new deliveries, cement was added for stabilization.
Added a small amount of cement will work wonders.
RE: How can I solidify excessively wet soils?
RE: How can I solidify excessively wet soils?
Frank Lucca M.I.Exp.E.
www.terradinamica.com
RE: How can I solidify excessively wet soils?
RE: How can I solidify excessively wet soils?
Frank Lucca M.I.Exp.E.
www.terradinamica.com
RE: How can I solidify excessively wet soils?
I'm with cvg on this one. Where would the water go?
Most of my clients would take a pretty dim view of even trying it. And with all of the military bases in my area (5 within 30 minutes' drive) the use of explosives is discouraged.
Please see FAQ731-376 for great suggestions on how to make the best use of Eng-Tips Fora. See FAQ158-922 for recommendations regarding the question, "How Do You Evaluate Fill Settlement Beneath Structures?"
RE: How can I solidify excessively wet soils?
The company with the most experiance in this is Vet's Explosives in Torrington, Connecticut.
Frank Lucca M.I.Exp.E.
www.terradinamica.com
RE: How can I solidify excessively wet soils?
Please see FAQ731-376 for great suggestions on how to make the best use of Eng-Tips Fora. See FAQ158-922 for recommendations regarding the question, "How Do You Evaluate Fill Settlement Beneath Structures?"
RE: How can I solidify excessively wet soils?
I dont think the authority will let you add a drying medium and have the material be used as a clean fill.
RE: How can I solidify excessively wet soils?
One of the big issues we are dealing with is the concept of drying vs. stabilizing. Drying is adequate for materials that need to be dried but do not need additional strength for bridging over soft soils. Stabilization on the other hand will result in strengths much stronger than the original soils and can often form a layer that will "bridge" over softer soils.
The issue here has been if drying is used it is not very complicated but if stabilization is proposed than the unconfined strength of the modified soil is measured and in the future credit may be given for this additional strength towards the pavement design.
Back to the original post, if drying is all that is needed it can be very inexpensive and can produce very quick results with the right additives and equipment. I have seen 3000 feet roadway stabilized in a period of a couple of days. One of the limitations is the equipment available. We have specialized companies here with large mixers(similar to the ones that mill asphalt)but they are still only capable of about 18" of mixing. The next question is how deep can the compactor effectively compact? We have found anything beyond 12" to be questionable. In cases where 12" of drying/stabilization was not sufficient we have done it in multiple 12" lifts.
This information may be more than anyone here wants to read. But I have worked with soil modification exstensively for the last 5 years and if anyone has questions I would be happy to try to answer.
RE: How can I solidify excessively wet soils?
RE: How can I solidify excessively wet soils?
Please see FAQ731-376 for great suggestions on how to make the best use of Eng-Tips Fora. See FAQ158-922 for recommendations regarding the question, "How Do You Evaluate Fill Settlement Beneath Structures?"
RE: How can I solidify excessively wet soils?
Good Luck!
RE: How can I solidify excessively wet soils?
Since it is now October, what was your final fix?
RE: How can I solidify excessively wet soils?
This is going to sound pretty obvious, but we noticed that the fill we had on site was still in the ground- it was only when we left stockpiles exposed to wet weather that we saw problems with compaction.
With a fair amount of finageling with the General, we saw big improvement using many rolls of visqueen and as many bags of sand and some timely off-days when the rain became excessive. I believe we increaced our time out there by at least a month and a half. The contractor had a special method of weighting the liners using twine for windier areas at the site.
This method in the end still left us with a few wet stockpiles, but for the most part was testing in the neighborhood of 7%, where previously I had readings upwards of 20%. I was surprised to be the only one excited on site! (I think the rest of them were sick of me :).
Anyway, for what it's worth, we're going through the same thing in the Evergreen State as well.
ds
PS. We also tried compaction of exposed stockpiles, but in the end liners proved far and away the best method for wet weather.