Tunnel Boring Machine

engineering · construction · machines

Giant underground mole. Tunnel boring machines are called "moles" because they burrow through earth like the animal does, but they're massive metal monsters instead of tiny creatures.

Spinning cutting head. The TBM has a huge rotating disc at the front covered in cutting teeth that spins and grinds through rock, dirt, and sand to make the tunnel bigger and bigger.

Perfect circular tunnels. Most tunnels made by TBMs are perfectly round, which is actually the strongest shape for a tunnel because the circular walls spread pressure evenly.

Faster than explosives. TBMs dig tunnels much faster than the old method of drilling holes, putting in explosives, and blasting away rock, making them the modern way to build underground.

Huge hollow spaces. Some tunnel boring machines can carve out tunnels nearly 18 meters wide, which is about as wide as five cars parked side by side.