Small underground tunnels can serve as passageway for your electrical wirings, water piping, or basically anything that requires transferring of one item to another location without the use of above ground means, using sturdy, leakage-proof tubing and materials. Before starting, you must first layout the direction of your underground tunnel.
After layouting, you should know the obstacles you could face in laying out the tunnels. For example, you might plan to build an underground tunnel beneath a heavily tiled or brick road. Creating an underground tunnel below it using the traditional method (digging) is obviously not safe.
This video aims to remedy this by exhibiting a foolproof way to make an underground tunnel without destroying the beautifully laid out tiles and bricks that were painstakingly plastered on the ground. All you need is your underground plan, shovel, sledgehammer, and, the star of the show, the PVC pipe.
source: Ask the Builder
Move on to the Next Page video: Underground Wire Tunnel.