Help! PHD won't go the distance

PaulT · Aug 14, 2003

Help! PHD won\'t go the distance

I need some advice from the TBN/CBN Community. I am building a pole barn, and I had planned to have a post-raising "party" on Saturday. Of course, that means that I need to get the holes dug before that. Tonight I went out to see how the 15" auger would work, and I dug 2 corners. Each one only penetrated about 2.5 feet. I need to get down 4 feet, so that the poles are below the 42" frost line. The thing is, I filled a pretty sloped area with what we call 4" minus (essentially 4" crushed rock with everything smaller, including fines, in the mix). The test holes were the low side corners, so they had a lot of this stuff. There is definitely more than 2.5 feet of it. I figured the auger would just dig right through, but it stopped short, and I'm not sure why. Perhaps that far down its not getting any bite on the 4" rocks. Does anyone have any ideas on how to get the PHD to dig deeper, or am I out of luck and need a PHD with downforce (i.e hire a man with a bobcat)? Everything I've read about PHDs says not to get off the tractor to apply downforce - very dangerous. What to do? I know you guys will help me figure out a way to do it myself with the trusty 2710 'bota if its possible. Any suggestions would be greatly appreciated. I will post this on CBN also, under barns/buildings.

Steven · Aug 14, 2003

Re: Help! PHD won\'t go the distance

sounds like its time to hook up the backhoe.
/forums/images/graemlins/smile.gif

PaulT · Aug 14, 2003

Re: Help! PHD won\'t go the distance

Yeah, I forgot about my favorite tool! The problem with that will obviously be --- very large holes. As the 4" minus is still very easy to stir up, I was hoping to avoid the large holes, especially since the low side holes are pretty close to the sloping sides. OK, I admit, I had so much volume to fill that I skimped on the runout slopes. /forums/images/graemlins/blush.gif They should be 3:1 at least. The fill is about 5.5 feet, so I should run it out 16 feet at the base, but I only went out about 7 feet so far. I plan to lay a bunch of large loose rock on the slope to hold it from a nearby pile my neighbor has, but I thought I could get away with doing it next week after the post-raising. If I have to get out the big blade from the swiss army tractor (the backhoe), then I probably need to reinforce the slopes first. I guess we'll keep the backhoe as the solution of last resort. At least I will be able to do it myself. Any other ideas that might get more mileage out of the PHD?

dummy · Aug 15, 2003

Re: Help! PHD won\'t go the distance

Not the safest way, but hanging weights on them has been done.

MikePA · Aug 15, 2003

Re: Help! PHD won\'t go the distance

I figured the auger would just dig right through, but it stopped short, and I'm not sure why. 
What kind of PHD do you have and how long is your 15" auger? I ask because there's no way the 9" auger I have could go down 4 feet. /forums/images/graemlins/grin.gif

When my auger has stopped digging, because the ground (clay) was too hard, no amount of weight on the digging head helped. /forums/images/graemlins/frown.gif

My advice...Get a Bobcat to finish the job.

PaulT · Aug 15, 2003

Re: Help! PHD won\'t go the distance

The PHD is a bush hog, med duty (not sure which model), The 15" auger is about 42" to the collar, but I have an extension for it. I have to get the auger in the hole before I attach the extension, though, since the total extended length prevents the 3ph from lifting the auger above the ground for transport. I still have at least a foot of travel available in each hole at this point before I need to add the extension for the last 6-12 inches.

I had a realization this morning while I was slapping at the snooze bar. Maybe the point is hitting one of those 4 inchers at the center of the hole, and the surrounding gravel is too loose for the flights to get a grip on, so it just churns in place. If I am right, I could take off the point, and let the flight chisels dig the rest of the way, but I don't want the threads for the point to fill up with dirt. Has anyone ever run into that or tried digging without the point in loose/soft gravel or earth?

WVBill · Aug 15, 2003

Re: Help! PHD won\'t go the distance

Paul: Do I understand correctly that a good bit of your 48" depth for your post holes is going to be in your 4"-minus fill gravel? If so, be very careful. Read other discussions here on TBN about setting poles for pole barns.

Now, as to your PHD problem, you are probably hitting a hard clay layer. When that's happened to me, I've had to take a digging bar and break up the layer for a few inches to let the flights on the auger get a bite. Others have put a bit of water in the hole and left it overnight to soften. Be very careful though because either of these approaches creates a pefect environment for screwing your auger into the ground.

When I put up my pole barn, I used a bobcat with hydraulic auger. It cut through the clay like butter.

Currmudgeon · Aug 15, 2003

Re: Help! PHD won\'t go the distance

( Paul: Do I understand correctly that a good bit of your 48" depth for your post holes is going to be in your 4"-minus fill gravel? If so, be very careful. )

Concur. That won't give you much lateral stability, and if it isn't compacted and confined, you may be able to punch a pile down through the stuff. I'd consider going deeper and using a bit more concrete. Not the answer you need right now. /forums/images/graemlins/smirk.gif

How about pulling the auger, busting the bottom of the hole with your trusty digging bar, and re-augering.

Or you could beat a long handled post hole shovel into a spoon, and complete the holes by hand, like they did in the old days. Depending on how many bad holes you have, this may be quicker than the drive to "Rent-All." Unfortuately, real pole hole spoons are hard to find. The people at the phone cpompany and power company don't even know what they are, any more.

PaulT · Aug 15, 2003

Re: Help! PHD won\'t go the distance

Yes, for the downhill side, it will all be in the new fill. However, directly beneath the new fill, only 6 inches lower is on old barn slab foundation that has been there for decades. The cement is still solid, andit definitely won't compact. As for lateral stablilty, I agree that I need to get the additional fill on the sides of the slope, but isn't that just a matter of weight and friction, rather than compaction? If so, then the mass of the stone I have to pile on the slope should hold. As I said, I plan to do that next week. I have read nearly all of the pole barn posts that I could find here, and I didn't see anything that really jumped out that I was taking a wrong/bad approach. If you are aware of some discussions that talk to this, please point me to those posts. I need all the help I can get.

As for the theory of hitting a clay layer, there is none there, since it is all that 4" minus I described (which, when compacted, is very nearly like cement. I have 1.5" minus - sometimes called crusher run - on my driveway, and it is hard as a rock). I should also mention that I ran a plate compactor over the site after about half the fill, and let it settle in hard rain for a week and a half before the second batch of fill was laid on.

WVBill · Aug 15, 2003

Re: Help! PHD won\'t go the distance

There was a pretty good discussion of pole embedment in This Thread

Also, when I built my building, I found a good discussion of pole embedment in This Book and in This one .