Prompt Cast
The History and Construction of Underwater Tunnels
TLDR This podcast episode explores the history and construction methods of underwater tunnels, including the use of tunneling shields, tunnel boring machines, and the immersion tube tunnel technique. Notable examples of underwater tunnels include the Saikan tunnel in Japan, the Channel Tunnel connecting the UK and France, and the upcoming Hong Kong-Macau tunnel.
Timestamped Summary
00:00
This podcast episode is about how underwater tunnels are built, including the history of tunnel construction and the different methods used.
04:24
Underwater tunnels were not successfully built until the 19th century, and some of the techniques developed during that time are still used today; tunnels are preferred over bridges because they can withstand tides, currents, storms, and carry unlimited weight.
08:12
The Saikan tunnel in Japan holds the record for the longest and deepest underwater rail tunnel, connecting Honshu and Hokkaido, while the Channel Tunnel connects the UK and France and the Marmaray tunnel in Istanbul is the first to connect two continents.
12:10
One of the oldest methods of building tunnels is called a tunneling shield, which was invented by Frenchman Marc Isambard Brunel and is still in use today. The tunneling shield is like a coffee can with holes in the bottom, and it is used to dig horizontally while providing support for the tunnel.
16:20
Digging tunnels requires a support structure and fresh air to prevent collapse and ensure the safety of workers, which is achieved through the use of tunneling shields and compressed air.
20:10
Tunnel boring machines are impressive mechanical engineering marvels that cut, support, and build tunnels all in one motion, and they were used for the construction of the channel tunnel.
24:30
The Immersion Tube Tunnel involves creating individual tunnel sections on dry land and then submerging them underwater to create an airtight seal.
28:46
Underwater tunnels are created by submerging individual tunnel sections, connecting them using winches and rubber gaskets, and then adding more sections until the tunnel is complete.
32:30
The proposed longest immerse tube tunnel in the world will connect Hong Kong to Macau and is expected to be completed in 2016.
Categories:
Society & Culture
