|The tip of the TBM seen from the Capitol Hill Station. The tunnel is in the background. The rest of the boring machine is still in the tunnel.|
|Here is a closer view of the boring tip, along with project manager Mike.|
Once inside the machine, there is room to move around. The total length of the TBM is about 330 feet, about the length of a football field.
Traylor, the company who build the University side of the tunnels, finished four months early. Here is what the roughed-in tunnel looks like.
As the TBM advances, they construct the cement tunnel lining behind it like a jigsaw puzzle. They then use the lip of the liner to push against to advance the TBM.
After tour, we climbed back out of the hole.
Mike says that people don't think about tunnels much. I think that that is true. I know that I'll think of Mike, the miners, and the machines that built them each time I go through a tunnel.
P.S. When I returned to my bike, here is what had happened.