4 ms·
Presumably tunneling through a mountain is much easier than underground because either end is just open. Very easy to get your boring machine into position / se
by fastball 6y ago
Presumably tunneling through a mountain is much easier than underground because either end is just open. Very easy to get your boring machine into position / service it when needed (by just pulling it back out into the open air). Also probably less issues with damp, etc.
- mauvehaus 6y agoTunnel boring machines (TBMs) bore a gross diameter hole that's then lined (often with concrete segments) for support. The net diameter of the hole behind the TBM is less than the diameter of the TBM, particularly the shield, which is the business end. Maintenance is done in place. Fun Chunnel fact: when the TBMs driving from England and France met, they drove one below the other and abandoned it in place. The other was dismantled and removed in pieces.