alt Hacker NewsBlasting through rock is expensive and only done if needed - I'd suspect that most projects now are cut and cover or tunnel boring machine - both of which can also be terribly expensive (see: Seattle).
Replies
rsynnott • today at 2:44 PM
Yeah, this one looks to be TBM for most of the underground sections.
Blasting through hard rock is easy. Finland has perfect rock and makes lots of tunnels with blasting. Soft rock needs support so TBM tunnels and shores up.