heave on piles?

[enginedave]

I was wondering about the behavior of piles when the load (which has been there for many years) is removed? Is there any likelyhood of upwards movement (as the load has been removed). Any good sources of information?
Many Thanks

 

[Zeccos]

I do not know any documented heave on the pile after a load is being removed. Heave on piles is likely to occur in expansive clays and the designer should account for that. However, for any case, if the piles are to be reused, retapping may be useful. If you observe that a pile needs retapping, it is likely that the rest will need also.
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Dimitris P. Zeccos
Graduate Student
Geotechnical Engineering
Department of Civil and Environmental Engineering
University of California, Berkeley

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[sgsibob]

I have never heard of "heave" on relieved piles either. However I would expect some elastic relaxation within the pile itself. In all probability the elastic relaxation of the soil loaded at the tip would be offset by the side friction resistance.