Piling Problem

[kieran1]

I have a situation where load bearing piles have been installed behind a proposed jetty. The contractor has said the piles were installed to refusal, which I doubt.

It is proposed to dredge the area under the piles after a concrete beam is cast, to a level 6.0m below water level. The piles are 11.8m long and top of pile level is 5.73m above water level. This leaves an embedment depth of only 70mm.

This is my concern. I was not involved until after the piles were installed. My thoughts are to not allow any dredging, but this will render the project unworkable.

Anyone any suggestions.

I'm thinking of sand bags in front of the piles to prevent the soil in this area from being removed. This is in Africa so tremie concrete and any solution which requires western technology is not possible. The jetty line is only 2.0m from the pile line.

Kieran

 

[Zambo]

Seems a good solution under the circumstances, sheet piles would of course be easier if available (Yes I know not available!).

I'm just wondering if lowering a concrete caisson in would be easier than the blocks. To describe what I mean let's assume your blocks are 1m(H)X 1m(W)X 2m(L). The caisson could be a 4 walled box 3m(H)X 2m(W)X 2m(L)so I assume could be the same size and weight as 6 of your blocks. After placing, the void in the centre of the box could be filled with concrete using a tremie.

For the sand bags why not fill with dry-mix concrete, the concrete will gain strength as it becomes in contact with water. If you have some of the slope you can access in the dry you could use a reinforced concrete slab instead of the bags.

 

[kieran1]

Thanks again Zambo for your suggestions always good to get another opinion.

I will certaining think about the caisson.

Kieran

 

[kieran1]

Thanks again Zambo for your suggestions always good to get another opinion.

I will certainly think about the caisson.

Kieran