Tunnel digging questions - water drill

[Bill Stock]

No, I'm not an inmate.

I want to dig a tunnel for some 3" PVC, roughly 5' below grade (12' long). I don't relish lifting the paving stones (again) or digging a trench 5' deep. So I'm wondering how successful the water drills really are? I've read good things, but it seems too good to be true. There's also a chance that the area contains fill with the odd piece of concrete/brick. If I use a 3/4" pipe with couplings I don't imagine I can hope for more than an 1.5" hole?

There's also these bad boys:

But one long enough to do the job would break the budget. I've checked the rental (Toronto) places online, but I haven't seen any yet.

Any words of wisdom on the water drills or better ideas?

[Proctologically Violated©®]

Well, you're going to have to dig a helluva pit just to work in, plus elbow room.

You might try dirt auger bits, used for digging post holes. They come in

2-3", up to 12" or so. Hoffman.

Since you might need a rotary hammer anyway, might as well just make an adapter and sectionable extensions, for both the auger bit and a carbide tipped drill for any rocks, etc. . My big Bosch is an SDS max, w/ variable speed, and not a very fast rpm, but a good wallop, which would probably be helpful even in the augering process.

You will have to do some welding, which can be tricky w/ tool steel alloys, so you might want to have a knowledgeable guy do it, or get recs from sejw. The extensions can be regular black plumbing pipe, w/ couplings. Hopefully you won't have to put anything in 'reverse". :)

[Rod & Betty Jo]

I tunneled under a 6ft sidewalk for a new water line simply with a QTR inch pipe connected to a water hose......super easy although I had no rock or solid obstructions. The small pipe helped with both increased pressure and limited water flow so the hole wasn't excessively too big.....Rod

[AAllc.architects]

I'll bet a hose will work. I've had folks doing similar work with - and here I'm out of my area of expertise - a device that is connected to the end of a hose that pulses its way through the ground. T

[BobK207]

The water drill can work but 12' is a long way!

My neighbor used an air powered "earth piercing torpedo" to "jack hammer" 50' from curb to house for a new water main..............no digging.

it was only a 1.5" torpedo but they come bigger.

here's a company near you

Be careful..........a 5 or 6 foot deep working trench can be deadly depending on the soil conditions.

You'll be at the bottom of that trench on your hands & knees ............augering or water jetting a 12' long hole?

Two engineers (in DIY mode) had a 3' trench collapse on them in Orange County, CA........neither survived.

How you considered hiring the job out to a company that does this sort of thing?

A sidewalk is pretty easy but you've got depth & length issues.....it isn't going to be easy.

cheers Bob

[Bill Stock]

My hole entry point is a small concrete room, exit is fairly flat hole. So collapsing is not too much of an issue, unless I have to dig the entire 12'. Soil is hard clay below 1'.

Probably not in the budget, plus I've got space issues.

I see stones/bricks being the big enemy.

[gfretwell]

If there are rocks in that clay it probably won't work. I would try some test bores straight down to see what you have Here in the Florida sand box I shot a 2" PVC 22 feet and hiit a hole a foot wide in my garage floor.. I made the drill head with a round cap and 4 holes in it. One about

3/8" in the center and three smaller ones around the edge about 1/2" in. Push and twist back and forth. Use an elbow and a couple feet of pipe on the far end to lever the twisting..

[Meat Plow]

How about a trained groundhog?

[sylvan butler]

...

I doubt your water drill will deal at all well with the random fill.

The custom augers are pretty cool. :) But I'd sure ask about your random fill before buying!

Directed boring. I've never looked at doing 3" PVC (just 2" and smaller poly). From the surface they run a machine that can cut thru the ground and pull the poly behind it, even cut thru your random fill. Not cheap.

For my run (about 150ft) they needed to dig a starting hole about 4ft square, a mid-point hole for a right-angle turn, and a termination hole to line up for the shot under the patio and thru the foundation wall into the basement. The price was cheaper to have the backhoe guy dig the entire trench, and go thru an adjacent crawlspace to the basement instead of under the patio. Either way I would end up fixing my lawn... I don't remember the numbers for sure... seems like it was over $2000 and under $1500, respectively.

OTOH, the gas company used the same technology to run the gas line under the road, thru the front yard and under the fence to the meter. Only problem was they punctured the 12" irrigation pipe parallel to the road.

sdb

[sylvan butler]

That room will fill up with water and mud -- everything from the hole ends up in the starting point!

sdb

[Bill Stock]

Yeah, I kinda wondered how deep I would have to go before the water started soaking into the ground and stopped blowing back at me. I kinda figured I might need some hip waders.

LOL, maybe some trained Gerbils might do the trick.