Building a tool

I've been on the phone today talking to rental centers about underground boring machines. I need to get under a 16' concrete drive to install a conduit. One place had some home-made rig for sidewalks that you drove thru with a sledge, but no one had anything powered. So, I thinking I need to build my own. I'll put my design thoughts out here for the brain trust to ponder and comment on.

As far as we can tell, I'll be in a mix of clay and fill dirt. Initial probing has found no big rock. We can dig down and out from both sides without restriction. I have to be 18 but would like to be 24 below grade. I'd like to run a 2 PVC conduit thru the hole. We have power, water, a mini hoe, skidloader, tractors of course and a few young men that can run a shovel. I'm thinking about 10' sections of 3/4 SCH 40 and a water nozzle, trench back 10' so the pipe is level when it goes under the slab, and push it thru with the skidloader. Feed it with a garden hose (or maybe pressure washer?) Probably take several stabs back and forth. If that works, add a section until we're thru the other side. Then pull a 1/2 cable thru and then pull the 2 thru the muddy hole with the cable. I'd make up a foot-long piece of 2 steel pipe with a cap and cable secured, and screw the PVC to a coupling to follow behind it. Pull on the cable with the FWA tractor. Whatchya think?

If it don't work we'll have a torn up muddy mess but some fun along the way.

I built a nose cone by cutting wedges in 3 pipe, heating it and hammering it to a point, Then I took a cap and welded a piece of 2X3 box tube to it. Our underground crew would put the cone on one end of a ten foot section of steel pipe and the cap on the other end, and using a tooth on the backhoe, shove it under driveways, removing the cap, and adding sections, as needed.

Back in '78-'79 I often ran a trencher putting conduit. A couple of times I had to put it put in under existing concrete. Best I can remember I did it much like you are planning except I don't think I did any as large as 2".

Use the conduit you wish to remain in the bore and feed a pressure washer hose fitted with a drain clearing head . Start the bore by hand then feed the conduit and hose in gradually . The waste and water will flow back towards you so have a pit ready to collect it , feed it in by hand . Most times you just need to bend the pipe to get it into the bore there isnt a need for a really long feed in trench or a spear head for the front of the pipe.
We have sandy soil here and this method will bore a 90mm stormwater bore two or three metres in less than an hour .

The folks that install residential gas lines have a gizmo that hammers itself along underground. Don't know what it is called. Check with local gas company. A friend (now retired) used one almost daily. HTH

I paid a guy to bore under road to install cable TV. Call cable company and see if they know a person who can bore under drive.
Joink is installed fiber optic pipe. They have a big boring machine.
George

That worked for me couple years ago. Except I did not have a skid loader to push the pipe.
I used 3/4 black pipe and rammed it back and forth by hand.

Where in Ia do you live? There are several good underground contractors that would do a good and accurate job for you.

If you are insistent on doing this job your self and you have the room, I would dig a trench 12' to 15' perpendicular to be the 16' drive, make a 2 1/2 to 3 diameter point for the the leading end of a 2 inch Rigid pipe not PVC. Rigid pipe comes in 10' lengths. So I would level and aim the point to a pit on the opposite side. Push the first 10' piece in with a tractor. Then reset the tractor and screw on the second piece of 2 rigid and push in the rest of the way. Unless the ground is really hard, it should go with a 100 + hp tractor. Then just leave the 2 rigid pipe in place. You should end up with 2' of 2 either side of the driveway. Have fun be safe. Call before you dig.

Hole Hog, needs air compressor attached.

Thanks. Now I remember the name.

Sounds like you have a plan.

Do use the pressure washer, I've bored under sidewalks just using the wand.

Cut like butter!

Seems like you are defeating your purpose to trench back 10' unless you need to anyway. Follow your plan and cut your pipe into 2' sections and just buy extra couplings. Slower but tear up less yard.

If you have anything with a right angle gear box like a post hole digger that could be rigged up could be an option.

Or use your conduit/pipe and do your own directional boring. Make a duck bill bit to control the direction maybe by cutting a scallop out of a coupling glued on to the end of the pipe. With your power washer or even a water hose with nozzle in side the pipe you won't really need to turn the pipe too much. Direction changes are made by orientating the bit and pushing on it. You can push it with the skid steer. [https://www.familyhandyman.com/list/basics-of-horizontal-boring/][/url]

Did you check with underground boring companies like mentioned below? Good friends just had a new well put in and hired one. Went 75, under a foundation, and right up through the center of a 1ft x 1ft hole cut in the middle of a slab floor. Pulled water line & conduit back through. What surprised him most was that it took longer to unload the equipment from the trailer than to do the job. Said it was 15 min max. Hes a believer now.

Concrete is probably not a problem, but my neighbor pushed a pipe under blacktop using water, and the next year the blacktop caved in!

(quoted from post at 13:53:41 04/12/21) I've been on the phone today talking to rental centers about underground boring machines. I need to get under a 16' concrete drive to install a conduit. One place had some home-made rig for sidewalks that you drove thru with a sledge, but no one had anything powered. So, I thinking I need to build my own. I'll put my design thoughts out here for the brain trust to ponder and comment on.

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You can drive a 2" conduit with a full size backhoe using the side of the bucket. 20' no problem. A rental mole and compressor works well also. https://www.powrmole.com/products/pneumatic-piercing-tools/

made a point on a 2 inch coupling and then dug a trench and shoved it under my drive with the backhoe.

A friend bought a tool at I think Home Depot that involved a garden hose and water,as he explained it you just fed the pvc behind it as it bored the hole under his concrete drive,he Lives in Houston and the soil is kind of sandy,said it worked great.

Your original plan will work. 3/4 or even 1/2" is flexible enough you don't have to dig a 10' trench. You can get by with a shorter one such as 2 or 3' and cut your 2" conduit accordingly. On your pulling end use a timber held down by a loader or the hoe to maintain your 2' depth when pulling the swedge and conduit through. If you are running service entrance cable, our power company requires 3" conduit which makes for an easier cable pull. 2" will work if you are running UF to an outbuilding. Conduit is cheap, I'd run the whole line in conduit to keep it dry. Run some 3/4" pvc/PE/conduit along with it for some cat 7 internet cable and some cat 5 for a phone line. Need 6" of separation between the two conduits. Don't forget some 3" red warning ribbon about 12" above the conduit when you bury the conduit through the yard. Lay the internet conduit under the tape and you have plenty of separation.

When planning all this out think about laying a gas line in a separate trench and same for a water line to the outbuilding. You don't want to add a water line later which has to be deeper than your electric.

Hire someone with a directional boring tool.


We hired a guy to go 75 feet under a barn with a water pipe. It was cheap compared to digging up a lot of concrete.

Try the water jet idea.
People in Florida sit posts in lake for boat docks using a 5 hp gas pump and jet water around post. Gets rid of mud. Post stops going down when you hit bed rock.

What if you put a rotating nozzle on a high pressure washer with extra long quarter inch pipe that you run inside plastic conduit? I would give it a try.
George

when I was about 10 we had to run a 1 1/4 water line under a barn 50 ft wide. we dug down about 6 ft and maybe 5 wide, 1 1/4 water line clamped to a 2 ft long metal pipe with a reducer to 1/2. Just hold the pipe level when you start to push it in. we had about 70ft of 1 1/4 line and just had that hooked to the garden house. no jet needed at the end just push it through. On the other side of barn we dug a trench and if I remember we missed are mark by 10 ft. we were going at an angle so were just guessing where it should come out. Didn't mater as we just used it where it ended up at.

Guy I used to work with used drill stem and pushed them under with his back hoe. The one trick he said was to always hold up on then end with the hoe to keep it from coming to the top.