Enormous Tunneling Machine 'Bertha' Blocked By 'The Object' 339
An anonymous reader sends word that 'Bertha,' the world's largest tunneling machine, which is currently boring a passage beneath Seattle's waterfront, has been forced stop. The 57.5ft diameter machine has encountered an unknown obstruction known as "the object."
"The object’s composition and provenance remain unknown almost two weeks after first contact because in a state-of-the-art tunneling machine, as it turns out, you can’t exactly poke your head out the window and look. 'What we’re focusing on now is creating conditions that will allow us to enter the chamber behind the cutter head and see what the situation is,' [said project manager Chris Dixon]. Mr. Dixon said he felt pretty confident that the blockage will turn out to be nothing more or less romantic than a giant boulder, perhaps left over from the Ice Age glaciers that scoured and crushed this corner of the continent 17,000 years ago. But the unknown is a tantalizing subject. Some residents said they believe, or want to believe, that a piece of old Seattle, buried in the pell-mell rush of city-building in the 1800s, when a mucky waterfront wetland was filled in to make room for commerce, could be Bertha’s big trouble. That theory is bolstered by the fact that the blocked tunnel section is also in the shallowest portion of the route, with the top of the machine only around 45 feet below street grade."
Paging Dr Quatermass... (Score:5, Interesting)
Re:Near the waterfront? (Score:3, Interesting)
Yeah, pretty much. But in this case, I will put my money on the hull of a schooner. Old piece of garbage got dumped there wholesale I'll wage.
150 years ago:
Person A: "Hey, we need landfill. Do you want this leaky decrepit hulk any more?"
Person B "Give me 20 bucks and it's yours."
Person A: "Here you go, thanks! That'll make great landfill and as long as anyone doesn't try to dig a giant tunnel through here, we're set!
Doesn't sound very stable... (Score:3, Interesting)
... having a 57.5ft tunnel with only 45ft of material above it. Aren't they worried about a cave-in? Unless they're plowing through heavily clay-laden (damned near bunker-buster-proof) soil like we have around where I live, surely the vibrations will have an effect on that 45ft of soil overhead if they decide to proceed and Bertha begins grinding its way through The Object.
Re:Scientific Term: BFR (Score:3, Interesting)
I'm no engineer but I'm guessing the machine was never meant to bore through solid rock like that. The procedure for rock is still drill-and-blast.
Actually; it CAN break up solid rock. The current guess is that the rock isn't staying stationary, but is instead spinning, preventing the drill from gaining purchase. By the time they're done, maybe it'll be a perfect cylinder :)
Re:Near the waterfront? (Score:0, Interesting)
Actually, the House has passed a budget just about every year. Only when the budget gets sent to the Senate does it get "blocked" as are all discussions to reconcile. The Senate hasn't passed a budget since Obama took office. (Though it sounds like they may have just passed some sort of budget this year -- for the first time but I'm unclear as to whether it is a real budget or just another continuing resolution with some changes added to it.)
Re:Doesn't sound very stable... (Score:2, Interesting)
Sorry... I'm not a civil engineer. I just thought it curious to be digging that large of a tunnel at that shallow of a depth and wondered if it wouldn't have been easier to merely excavate a trench that you fill in later once the tunnel is complete. As I recall that's how some of the early subways were constructed. But I guess that you are a CE so I'll defer to your expertise. Finally, I realize this is /. and there's no firm requirement for someone to answer a post with a thoughtful correction but it's too bad that you felt it was it necessary to be a douchebag about it. Jeebus... Usenet groups were more civil.