Auger Cast Piles

[chahnz]

Gentlemen,

I have the following questions concerning Auger Cast Piles:

1) How does the spacing of the auger flights affect the installation of an ACP? For example, if a spacing of 9” is specified between flights, and a spacing of 12” is used, will the integrity of the pile be affected?

2) DFI recommends using a cork as a tip plug. I have seen the cork get pushed up the auger causing the hollow core to jam up. As a result the pump became clogged and the pile installation had to be stopped. Are there any other types of tip plugs that can be used in place of the cork? (Also, could it be possible that the grout pump is creating suction within the system and sucking the cork up the hollow-stem auger?)

Thank you in advance for any help

 

[GeoPaveTraffic]

12" auger flights should not make any difference. I would consider the spacing of the flights to be "means and methods"

As for the plug, cork (real or synthetic) is all that I've seen used. I really doubt that the pump is pulling a suction, more likely just a combination of groundwater levels, soil type and cork size. Sounds like they need a slightly larger cork or that they need to weld bead around the plug hole.

 

[Speedycrete]

I am a concrete pumper, I was involved in some of the piling work for a project in town that used this method. The piling company had a 'Soilmec' rig. They used a steel plug that had a wider flange on the end to keep it from being pushed in. I also believe that there was an o-ring to give it a snug fit. This was also attached to the auger piping with a sturdy chain so it could be recovered. Of course, in over 1000 piles, they did lose some of the steel plugs, but they had quite a number of spares.

It may have had some sort of keyway to lock it in place and keep it from spinning as the auger was digging, I don't recall.

I seem to recall they said that the manual that came with the unit recommended a sacrificial hardwood plug be used for each hole. I'm sure that would have kept some woodworker with a lathe very busy.