13M views · 59K reactions | Mary, the tunnel-boring machine, made its final breakthrough on the new Hampton Roads Bridge Tunnels Wednesday. Gov. Glenn Youngkin and U.S. Secretary of Transportation Sean Duffy were in attendance for the historic moment, marking a major milestone in the HRBT Expansion Project — a nearly $4 billion project that has taken almost 17 million man-hours. The new tunnels are expected to open by spring 2027. | WTKR News 3 | Facebook

Mary The Tunnel Boring Machine’s final breakthrough! #HRBT | Virginia Department of Transportation

This machine tunnels through literally anything, even mountains 🤯 | UNILAD Tech

26K views · 227 reactions | world's largest tunnel boring machine | Discover World | Facebook

How does Tunnel Boring Machine (TBM) work? A Tunnel Boring Machine (TBM) is a specialised piece of equipment used to excavate tunnels through various types of soil and rock. It works by using a rotating cutter head with sharp disc cutters or tools that grind away the material in front of it, creating a tunnel of a precise diameter. As the cutter head rotates, the TBM simultaneously removes excavated material through a conveyor system and supports the newly created tunnel walls with precast concr