How to auger a 18" hole through sand that's collapsing

[Ken45101]

For the sonotube to drop down into the hole, the hole has to be bigger than the sonotube. This would leave a gap around the footing.

That depends on how loose the ground is. If it's loose enough, it will fill in against the tube.

 

[orezok]

That's true, but would you want the footings on your building located in loose soil in a sonotube that lacks any soil friction or lateral support? Most structural engineers will not allow sonotube below grade unless it is engineered that way.

 

[Midniteoyl]

What I have always done is dig the hole, bell the bottom, fill half way or so, then sonotube the last foot or so.. Gives nice footing on top, but allows the ground to resist heave.

 

[vtsnowedin]

I'm wondering why they placed and compacted the sand before they poured the footings? It would have been a lot easier to drill them into the firm subsoil then compact the sand around them. It still might be easier (and cheaper) to pile the sand off to the side and bring it back later.

 

[Danno1]

I'm wondering why they placed and compacted the sand before they poured the footings? It would have been a lot easier to drill them into the firm subsoil then compact the sand around them. It still might be easier (and cheaper) to pile the sand off to the side and bring it back later.

I believe the sand is part of the natural geology in those parts.



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