You’re probably surrounded by massive infrastructure projects, with precisely zero idea about how any of them came to pass. What kind of man are you, huh?
Well, this should help: The Washington Post has produced a ginormous infographic detailing the tricky process of digging the 2,400-foot subway tunnel that’s slated to bring subway service to Tyson’s Corner in Northern Virginia.
Normally, the easiest way to dig a tunnel–the way old-time subway engineers relied on–was to simply dig a huge trough, build the tunnel, and cover it back up with dirt. That’s being used here, at the beginning and end of the tunnel. But there’s also a cutting-edge “Austrian Technique” being used to speed things up.
It’s all about a highly choreographed sequence of moves: First the ceiling is jammed with steel rods, which reinforce the top of the soon-to-be tunnel. Then the top half is excavated; during the process, the exposed earth is lined with girders and sprayed down with “shot-crete,” which stabilizes everything. Then the bottom half is excavated and reinforced with girders and shot-crete. And here’s what’s really stunning: The machines are precise enough that they align the sections within one-millimeter tolerances. Lasers monitor the walls, to make sure everything’s going right. The workers and machines are able to dig about five feet a day.
Total cost: $85 million. Or, about $35,417 per foot of tunnel.
For the full-sized version, and more information, check out The Washington Post. And after that, retreat to your man cave and roar mightily! Rar!