How does a tunnel boring machine work?

What Crafty Clover says in this video

Intro

Hi there, curious minds! I'm Crafty Clover! Let's discover something amazing. How does a tunnel boring machine work?

The Big Idea

How do people dig long tunnels under cities? They use a giant machine called a tunnel boring machine. It digs and builds at the same time!

Cutting Wheel

Step one: Cutting Wheel. A tunnel boring machine, or TBM, is a giant tube with a spinning cutting wheel at the front. Hard metal discs on the wheel grind through soil and rock.

Conveyor Belts

Step two: Conveyor Belts. Conveyor belts carry the broken rubble out the back. Trucks or trains take it away.

Building Walls

Step three: Building Walls. Behind the cutter, the machine builds a ring of concrete pieces to line the walls. Then it pushes against the ring to move forward again.

A Closer Look

Let's take a closer look! The cutter spins. Rubble rides out. Concrete rings line the tunnel. The machine pushes ahead.

Quick Facts

Quick facts! Some tunnel boring machines are as long as a football field. Tunnel boring machines are often given names. A TBM moves forward slowly but steadily, day and night. TBMs dig subways, road tunnels, and water tunnels.

Think Like a Scientist

Now, think like a scientist! Roll out some soft clay or play dough. Press a round cookie cutter into it and twist. Pull out the round shape. How is that like a TBM cutting a tunnel? What would you use to line the walls?

Outro

A tunnel boring machine has a spinning cutting wheel that grinds through rock, conveyor belts that carry rubble out, and a system that lines the tunnel with concrete rings as it moves forward. Science is amazing! Keep wondering and keep exploring! Share what you learned with someone at home, and see what they think! Crafty Clover can be found on Amazon Books, Google Bookstore, and Apple Books. Available for purchase or download! Bye for now!