How China Built a 6.7km Undersea Tunnel That Changed Coastal Travel

It looks like a bridge, but suddenly it vanishes beneath the ocean. Discover the insane engineering behind the Hong Kong-Zhuhai-Macao Bridge (HZMB) and why building it required turning the seabed into rock.
The HZMB is not just the longest sea-crossing in the world; it is an engineering paradox. Located between a busy airport and a massive shipping lane, engineers couldn't build high, and they couldn't build low. The only solution? An underwater tunnel.
But digging a tunnel here was thought to be impossible. The seabed is covered in a 30-meter layer of soft mud—like "peanut butter." A standard TBM (Tunnel Boring Machine) would get stuck instantly.
In this video, we decode the step-by-step engineering process behind this "impossible" tunnel:

The Foundation Challenge: Using Deep Cement Mixing (DCM) to turn soft mud into a solid base.

The Factory: How they cast 80,000-ton concrete segments on land using an internal cooling system to prevent thermal cracking.

The Installation: Sinking segments with millimeter precision using GPS and Sonar.

The Connection: Utilizing hydrostatic pressure (the ocean's own weight) to seal the joints naturally without bolts.
#china #engineering #tunnel #documentary #megaprojects #construction #chinainfrastructure
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