Frost Heave

[phonedesk]

Hello,

I have a lightweight structure supported by multiple H-piles, and I'm trying to quantify the frost heaving force on an H-pile. I know there's very limited research on this topic, but I was wondering if anyone knows (or knows a geotechnical engineer who knows) how to quantitatively design for such forces. The only equation I've found is Dalmatov's adfreezing equation:

F = L*h*(c-0.5*b*Tm)
where
F = frost heave force on the pile (kgf)
L = perimeter of foundation in contact with the frozen soil (cm)
h = thickness of the frozen soil layer (cm)
c and b = soil parameters (kgf/cm^2)
Tm = minimum soil or surface temperature (C)

While this is very helpful, I can't solve the equation without knowing the site-specific soil parameters 'b' and 'c'. Are they standard terms that a geotechnical report would yield? If anyone has any insight, it would be greatly appreciated!

(Also, I know that frost heave can only occur if the soil has the right porosity, water/moisture is present, and freezing temperatures occur. However, I can't use the typical "cheats" of changing the soil conditions via backfill, or using an expensive type of pile with a collar, or any other technique, as my project budget doesn't allow for it.)

 

[oldestguy]

Check with University of Wisconsin Extension, Dept. Madiso9n, WI.

They have been known to do studies on ice heaving of docks in Lake Superior and similar situations.

Can you at least describe the soil type as to gradation? Some soils are aggressive and others no problem. The P-200 fraction would say a lot.

 

[oldestguy]

The Canadians should have plenty on this. I tried a search for some info but see there is a whale of a lot. This is only part of what I came across.

U.S. Army Cold Regions Research and Engineering Laboratory (CRREL)

• U.S. Permafrost Association website:

http://www.uspermafrost.org/education/PEEP/ptf-manuals.shtml

• CCHRC library and website:

http://www.cchrc.org/permafrost-technology-foundation-library

•  UAF Cooperative Extension Service online publications at

http://www.uaf.edu/ces.

Geophysical Institute, University of Alaska Fairbanks

A search for "frost jacking" also may turn up info.

 

[oldestguy]

Doesn't look like a lot of help showing up.

I did a search for "compressive strength of cold ice" and a lot came up.

One has some data.

http://web2.clarkson.edu/projects/iahrice/IAHR 2006/contents/55_s102.pdf

Assuming that ice works like any other brittle materials the shear strength probably is half the compressive strength.

 

[DBronson]

PD:

You might check out the following paper (available on line). It has a section on frost heave forces on piles and a discussion of the Dalmatov equation. Incidentally, according to the paper, several on-line sources have the incorrect values for b and c listed. There's a table with the values for several soil types in the paper.

"AXIAL CAPACITY OF PILES FOUNDED IN PERMAFORST:A CASE STUDY ON THE APPLICABILITY OF MODERN PILE DESIGN
IN REMOTE MONGOLIA" by Scarr and Mokwa

Regards,

DB

NB: The "Design Manual for New Foundations on Permafrost" has a discussion of frost action on H piles. Available on line.

 

[BigH]

Google the attachment title; I think that this might be what you are seeking . . .

 

[phonedesk]

Thanks for the feedback, everyone.

oldestguy, I couldn't find a paper at UW Madison Extension. Do you have a specific reference in mind?

DBronson, I've been referencing that paper, as well. One problem is in the detail below that table, which states "These value are site specific and should be used as an initial estimate." Another problem is that the classifications listed don't correspond to ASTM D2487 soil standards (which I'm assuming is the standard for American geotechnical engineers?). I'll likely get a geotechnical report for each project for which I need to design the H-piles. However, I'm not sure if any of the information I'll receive would directly reference those 'b' and 'c' parameters, or if they can be somehow determined from the information in a geotechnical report. Thanks for the reference to the "Design Manual for New Foundations in Permafrost". That's one I hadn't seen before.

BigH, that attachment name is simply "Russian_". Could you just list the name?

 

[oldestguy]

Mr. phone desk:

I did some phone calling and the UW Extension and learned they have an office specifically devoted to special, situations and such at Superior,WI

That office phnoe number is 715-395-1363. The area you might be interested in is at 715-395-1547

I also do have a name and his e mail address, but I am not sure if the WEB managers here want such things published. Calling the last number will give that, with initials GA or JA, I'm not sure.

 

[BigH]

Try this - it is a jpg file of the title, authors and abstract - which is what I had posted before - I don't know why there is a mess up,

The paper's title is: "Russian and North American Approaches to Pile Design in Relation to Frost Action" by Bernard Nidowicz, Yuri L. Shur and Harding Lawson Associates Inc.