Compacting gravel under water

[aeoliantexan]

We need to backfill conical depressions about 8 feet deep around large drilled piers at the bottom of a lake. The water depth is 55 feet. We propose to place gravel or crushed stone through a tremie, but don't know how to get any compaction. We can use a diver. Are waterproof concrete vibrators available? Any other ideas to get moderate compaction would be appreciated.

 

[Ron]

Depending on the gradation, you probably don't need supplementary compaction. Anything from #89 stone up probably won't benefit from supplementary compaction.

 

[BigHarvey]

You can use dynamic compaction or just vibrating an H-pile with a vibrodriver.

 

[oldestguy]

If they are still around, the vibrating spuds used for the Vibroflotation procedure would easily reach there and shake the hell out of anything near it. You need a crane with well over 55 feet of boom.