This is also a technique that was used more than 100 years ago for the line 4 of... | Hacker News

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		padenot 7 months ago \| parent \| context \| favorite \| on: The Evolution of Tunnel Boring Machines (2023) This is also a technique that was used more than 100 years ago for the line 4 of the Paris métro: https://www.ratp.fr/en/discover/out-and-about/culture/histor...

llsf 7 months ago [–]

Funny that they had to freeze the ground to dig it, as it is one of the hottest line in Paris (at least 20 years ago).

s1artibartfast 7 months ago | [–]

My understanding is that the freezing is normally about stopping water intrusion long enough to drill and place concrete

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