I'm digging a new sprinkler system before the weather here gets too hot to do it. Part of the fun is laying a sixteen-foot tunnel out of one-inch Schedule 40 PVC under the driveway.

[Update at 4 PM EDT]

In response to the question in comments, I use a hydraulic drill. The soil is sandy (this wouldn't work if it were rocky or clay). Attach a straight nozzle (Home Depot sells them just for this purpose) to one end of a twenty-foot length of PVC, and a hose connector to the other. The jet of water blasts a hole ahead of it to allow it to be pushed underneath the concrete. Unfortunately, the longer the run, the more friction on the sides of the pipe, particularly from the junction that sticks out, and the last few feet require a hammer to get it all the way through. I don't think I could manage a wider driveway than I have. Once you're all the way through, cut off the hose connector and nozzle, and hook up the pipe to each end.

How do you dig such a tunnel? I've always wondered about that.

Some years ago, I put an extensive watering system on an already well developed half acre lot. I had to go under a driveway, under retaining walls, under walkways, etc. Sometimes I did lots of digging, sometimes used hydraulic tricks, other times a long metal pipe, a sledgehammer, and lots of pounding. Fun, fun, fun!

Now's your chance to embark on a life of crime, VR. Sounds like you already know how to break out of stir.

Up here in the land of red clay those hydraulic tricks don't work since your just turning hard clay into sticky super-glue that keeps your pipe just where it started, no matter how much pounding. I did a drip irrigation system that had to go under one sidewalk so I had a sacrifice piece of steel pipe that was larger diameter than the PVC. I basically used it as an auger, hammering it in and pulling out plugs of clay until I emerged out the other side.

I stupidly did it in August, too....

The next time I'm hiring someone to do it.

Neat trick. Thanks for the education.

Cheers

--Fred

Back in the late 60's early 70's we used to do expansions and maintenance on water systems and sometimes had to punch lines under roads. We'd use a similar trick. We'd push a steel casing pipe under the road using a backhoe to apply pressure, and a jackhammer to bang it through. Then we'd run the water line through the casing pipe. Had the advantage that if the pipe developed a leak under the road you could cut it off and replace a length without having to punch it under or dig up the road again.