Some people dig tunnels to make trade routes shorter or roads more direct; some dig escape tunnels; and some dig just for the engineering challenge. You can dig your own tunnel in the soil on your property. Remember the hazards if digging and never dig alone. Hand tools suffice for small tunnel projects; the only constant is shoring. Keeping the ceiling braced helps your tunnel to be more stable.
Don safety gear. Dig the tunnel out with a shovel, using plastic buckets to haul out the dirt. Take your time and make the dimensions of the tunnel large enough for your body to fit through without touching the sides of the excavation.
Loosen any compacted dirt and rocks with a digging bar. Do not dig the point of the digging bar into the top of the tunnel; this may cause the top of the tunnel to collapse.
Cut the lumber with a circular saw. Make one piece of lumber long enough to fit across the top of the tunnel. Cut two lumber pieces high enough to use as braces on either side of the top lumber.
Place a board across the top of the tunnel. Place a board up each side of the tunnel to hold the overhead board in place.
Nail the uprights to the overhead board with 16d galvanized nails. Place a new wooden brace every six feet along the entire length of the tunnel.