Is technology really the slow and expensive part of boring tunnels? To me it has always seemed that tunnels are expensive because: * Planning the traffic impact and how it interacts with other transport lanes, all the above-ground building work to make the tunnel useful, * Emergency ventilation and escape routes, and all other infrastructure that goes into the hole, * Avoiding any building foundation piles, unmapped…
I believe they're hoping to mitigate 3 and 4 by going deeper than most things. But wouldn't that make 2, emergency escape routes, a lot more expensive? How do you make a very long, very deep, narrow-diameter, elevator-accessed tunnel safe from fires and toxic gas releases? You can make it a vacuum but then what if you have to escape a vehicle? How does this thing not become a death trap in the event of a fire? Fire i…
The Channel Tunnel is only 31.5 miles long vs 230 miles (driving) from New York to DC, but having an access shaft every 30 miles or so wouldn't be that bad.
I'm not sure how you'd deal with the vacuum issue though - I guess doors at regular intervals that can be sealed, so a section of the tunnel can be bought back to atmospheric pressure, and the emergency doors can be opened between the car-tunnel and tunnel-emergency tunnel.