I really have no idea what's going on here.
So first they dug these narrow, deep holes and dropped girders in.
Then they dug thin trenches between them and poured walls.
Then they excavated out the dirt between those walls! What?
This city is under constant construction, so I've seen a lot of basements and foundations being dug, and I've never seen it done in that order before. They always dig a hole, shore up the sides as they dig, and then pour the walls. This seems like way more effort.
So next, they dropped girders on top of the hole, at street level, presumably to hold up the street that's going back on top -- except they only left like 4' underneath the girders, so what's going under there? Why did they do this at all! I thought the point of digging this hole was to build the head-end for the drilling machine, meaning the receiver for a bunch of conveyor belts trailing behind a chewing disc that is around 20' across.
What the fuck are they doing? Their blog is pretty good with the updates about what they're doing right at this moment -- "we're pouring walls" -- but there's absolutely no big-picture overview that I've found that explains what specifically they're building or in what order. What's the thing under the freeway going to look like? Where exactly does the drill go in? Are they manufacturing tiles on site or shipping those in? The animation was awesome, but not specific to this project.
The plan set for this project must be thousands of pages, and I suspect that the first 4 pages would explain everything I want to know, but I don't know where to find it.
And most importantly, once that drill is in the tunnel, how do I get a tour?
Related: I still have not been on top of the new Bay Bridge span. Hook me up.