Hydrovac excavated pile capacity
Hydrovac excavated pile capacity
(OP)
Hello.
Could anyone direct me to papers or documents with info
on how to determine friction/bearing capacities for piles
advanced using hydrovac excavating?
Any links or direction would be greatly appreciated.
Thanks,
Corey Dale
cdale_shelbyeng@hotmail.com
Could anyone direct me to papers or documents with info
on how to determine friction/bearing capacities for piles
advanced using hydrovac excavating?
Any links or direction would be greatly appreciated.
Thanks,
Corey Dale
cdale_shelbyeng@hotmail.com





RE: Hydrovac excavated pile capacity
RE: Hydrovac excavated pile capacity
I haven't seen any - I assume that you have checked the usual references (GT Journal, Geotechnique, etc.)
Personally, I don't have any experience with this technique (at least not with a construction method by that name.) Can you provide some additional details about the site and hydrovac construction in general?
RE: Hydrovac excavated pile capacity
A hydrovac'd pile is simply a pile hole excavated using a high pressure water stream to blast the soil, and a vacuum truck to subsequently remove the material blasted away by the water. This type of excavation is used when the pile is to be located near existing buried ulities so as to not damage the utilities.
A hole with very rough sides is created. Our feeling was that the skin friction would actually be greater than that of a bored friction pile due to the much rougher sides, but we treated it as a regular skin friction pile to be conservative.
Regards,
Corey Dale
RE: Hydrovac excavated pile capacity
My gut says that piers constructed this way should be adequate, but my gut doesn't have an engineer's license...
RE: Hydrovac excavated pile capacity
There are strong caveats for drilling deeper with hydrovac, not the least of which is that depending on deeper soil layers/materials your pile might be a whole lot larger in diameter than you expect, even to the point where you could fail adjacent structures. The deeper you go, the harder it is to see what is actually happening. And in some circumstances even shallow excavations have resulted in undesirable effects (such as cave-ins) due to a sandy-gravelly layer washing away, rather than cutting a relatively nice clean hole in some clay/clay till.
Discussion with a colleague reveals that while he has never seen a different value for friction capacity, he has seen higher values suggested by the geotech for frost jacking effects.