Organic soil

[sundream]

I have a project in a site with muck soil
I am wondring if anyone has recommindations about building on organic soils without removing it?

 

[GeoPaveTraffic]

Yea, don't do it.

 

[sundream]

What do you mean?

 

[SlideRuleEra]

Done all the time on the coastline - drive piling, sometimes very long ones to reach soil suitable for end bearing or skin friction.

http://www.SlideRuleEra.net

 

[rchanke]

New construction on organic soil profiles happen all the time. These sites are commonly remediated with cement injection ie. Soil Mixing. Google "soil mixing" and you'll find several ground improvement specialty contractors.

In situ soil mixing can treat a wide range of soil types, and this treatment can vary depending on applied mix energy and reagent binder type. Soft cohesive soils are usually targeted as other technologies can treat other soil types more economically. The mechanically mixed Wet Soil Mixing system does create a spoil material (when the reagent binder is injected in slurry form) consisting of a mix of soil and slurry binder. This spoil will solidify and can usually be used as a fill material elsewhere on the project. Alternatively, injection of dry cement powder can be performed where a high water content is present, Dry Soil Mixing.

Cohesionless soils are typically easier to mix and blend than cohesive soils. Cohesive soils vary widely in their ability to be mixed, depending on the soil type, strength, water content, stratigraphy and texture. Organic soils may require significant quantities of binder or pretreatment, and laboratory testing prior to production is recommended for all projects. The laboratory tests typically reveal the unconfined compressive strenths that can be obtained with a given binder type and dosage.

 

[eric1037]

Depends on the building size, depth of organics, depth to groundwater, etc.

More info would be helpful.

 

[BigH]

Depends on characteristics of muck - just mud? or amorphous/fibrous peat. Besides some of the above, careful installation of wick drains, surcharge loading and the like can be done. Also, can consider to use the rolling surcharge method (this is described in Tshebotarioff 1951 - from Michigan DOT of 1947). I used it and successfully displaced some 40 ft of slimy tailings in South America. If needbe, can also use explosives to remould the material even further and then use displacement methods as I noted above.

GeoPaveTraffic's comment, though, is not one to dismiss. One needs to be aware of the complexity and careful attention needed in applying all other than, say piles (although there would be other non-pile issues), to a project built on "loon shiesse". Sometimes, it is best to walk away from a project that might not get you enough revenue to make the risk acceptable. Risk analysis is not always about the project foundation type, etc. It is as applicable to the firms involved. Also, it might be best to advise the client (potential) client about the risks - and by all means if you go ahead, keep the client forewarned about the risks, etc. (keep it in writing, etc.)

 

[oldestguy]

In addition to the need for "more information" as indicated above, find out what has gone on in the neighborhood for other jobs? Generally the past practices have had rather extensive checking of costs and success, etc. so that they maybe have done a lot of research that you might not have to duplicate.

I don't often see here anyone recommending "ask local contractors". Even though they may think they are experts, I find many contracting firms are run by PE's of considerable knowledge and usually very eager to give good and practical "free advice" (worth the price?). It's always nice to have developed friendships with these guys since one never knows what may develop in the future

When it comes to surcharging, the cost of haul in of material and use of it later may be important.

Soil mixing with cemeting agents is not common in our area and I'd use that as a last resort,as well as piling, unless such area practice is comon.

Then too the type of foundation comes in the picture Can it be built to allow minimum differential settlements and still have a usable structure above it . If so maybe no special site reatment is needed, or at least minimal expense site treatment.

By the way I'm 78. Anyone older?

 

[Floodwall]

Every job I've done in the past twelve years has been in "muck".

As we say in the New Orleans area "a driven pile is a tested pile"

Piles are a way of life here - even for most residential structures.

 

[boo1]

Floodwall, how are the piles (wood) attached to the concrete stemwall footers?

 

[BigH]

OldestGuy - you've got me beat by a few years! More power to you and your comments on asking local contractors is a good one. I always found them helpful when I was more practicing on a daily basis than I am now (long term construction projects).

 

[Grouser]

samaryounes

You have not responded to any of the questions posed by those folks gracious enough to answer your post. In particular, the proposed use of the site is necessary for the body eng-tips to assist you.

A structure on the site may be able to be adequately supported by any of the techniques proposed but what of the eventual consolidation of the muck? Access to surcharge material, piling yards, etc. and site access are important. Is there an environmentally important feature on or near the site that needs to be considered? Weather conditions that may affect construction? (site locale) On the cheapskate side, what happens if you build on the muck?

We would like to help you. Give us some information to enable us to do so.
Cheers