"moulds, rob" wrote:
> Does anybody have any experience or references / information relating to
> driven tubular steel piles with end bearing plates. The plates are
> however not welded across the base but are positioned approx. 5-8
> metres up the inside of the pile.
>
> The piles are to be driven through chalk gravel into a moderately weak
> to moderately strong chalk
>
> Particular concerns relate to the effectiveness of the plate to create a
> 'plug'.
>
> Thanks
>
> Rob Moulds
Rob and others on the list
I have two experiences of driving tube piles with end plates, both of which
were problems and which are unpublished.
The first in the UK at Lowestoft with the plate about 1.0m inside from the
toe with a pile dia of 750mm. The piles were driven through Made ground
(cohesive and granular), Med dense fine sand into a dense clayey silt at
about 20m. The piles pulled up immediately they reached the silt, for
various reasons it was necessary to drive to depth for lateral stability and
to make driving easier we cut out a hole 350mm dia in the plate to relieve
some of the end bearing.
The second was in Dubai driving 750mm dia piles again with the end plate
about 1.0m from the toe. Here the piles were driven through loose sand into
weak calcisitite with band of weak sandstone, ground water at ground level.
The piles drove to about 10m when the driving suddenly eased and the piles
filled with water. The piles were extracted and it was found that the end
plates had been blown in, presumably by the pore water pressures generated
by the hammer. The problem was cured bu burning four 100mm dia holes in the
pile wall just below the end plates, all piles then drove to the required
depth / set without any problems.
Hope that helps, photo available for the Dubai case
Regards
Steve Corbet
Associate Maunsell Ltd
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