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Amazing that they managed to fill two whole pages of speculation about what might be under that bit of Seattle without once mentioning the giant underground city that actually is under that bit of Seattle. Or at most a few blocks away:
http://en.wikipedia.org/wiki/Seattle_Underground
They talked to the local city librarian, so clearly she must have mentioned the tourist attraction where you can go down and see all the buildings that sank into the mud before they decided to raise the street level, oh, around 45 feet.
So now when they're digging a new tunnel 45 feet under that spot, it's tough to understand why they're in any way surprised that they hit something building-ish.
I laughed when I saw the map. Compare [1] from the article with [2], which mostly corresponds to the location of the Seattle Underground.
I went on the Underground tour earlier this year. It's really interesting and pretty funny too; after a large earthquake at one point they used the tunnels to hide a lot of the debris. I'd definitely recommend the tour; that said, I would definitely not want to be down there when something like this hits the wall!
A big object blocks Bertha. What is it? http://lmgtfy.com/?q=Seattle+Underground
[1] http://graphics8.nytimes.com/images/2013/12/20/us/20tunnel-g...
We (my family, i.e.) personally found that tour rather short and significantly overpriced at $17 for about 75 minutes... in spite of that it was packed with tourists who paid extra for priority seating at the start of the tour (which isn't worth anything in practice). A real money spinner.
please don't use lmgtfy
Looks like you missed this. Paragraph 7:
> 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.
>"Looks like you missed this."
Or not.
When I read this yesterday, knowing nothing of Seattle history I felt a lot like what the parent is expressing because of the quoted bit.
The article spends 1200 words basically forcing speculation on "the object" (So ominous!) and casting a load of preemptive ("want to believe") doubt on an obvious explanation.
It's the scripted "reality" TV analog for news - manufacturing suspense from the mundane.
That said, I do hope "the object" is in fact an alien spacecraft.
I find it fascinating that the pressure is so high in their (relatively shallow) drilling area that the people doing the inspection have to go through decompression chambers. I'm trying to visualize how that could be, but I'm not sure what's going on - is there basically a "perfect seal" in the front of the drill head they don't want to break? And if so, won't the bore holes they are drilling do just that?
That's the most interesting part of the article for me.
Large TBMs like this generally allow access to what is called the face (the area being excavated) via a double bulkhead system. The ground conditions in Seattle require that the machine be able to control the rate of excavation at all times such that a large sink hole does not form due to uncontrolled loss of ground. This is done by keeping pressure on the face.
The pressures required to keep the face stable are a function of the soil properties, lithology, and groundwater. The typical way for someone to access the face is to pressurize ahead of the machine head with gas and have workers enter under pressure (known as a dive or an intervention). Workers generally are limited in how long they can be under pressure and must go through decompression.
Edit: real quick calculation on my phone puts them at about 70 psi or 4.5 atm of pressure to do a manned intervention, possibly higher for safety
Disclosure: underground tunneling is my profession.
I've always wondered how they get the kind of seal necessary to maintain that kind of pressure ahead of a tunneling machine. Is the drilled surface smooth enough to provide that kind of seal?
>Disclosure: underground tunneling is my profession.
That is the best thing I've read all week :) That's an awesome job! How common is that? Do you get hired for individual contracts, or are there entire companies that tunnelling is what they do 24/7?
http://www.wsdot.wa.gov/Projects/Viaduct/Contents/Item/Displ...
Top of the boring machine is 60 ft from the surface, but it's 60 ft high so bottom of it is 120 ft. That's 120/33 = 3.6 atmospheres in the ocean, and my reading of the article above is that it may even be higher here due to groundwater pressure. Anyway, you need decompression at anything over 1 atmosphere given enough time as I recall?
Edit: fascinating machine. So yes, it maintains pressure in front of the drill head to resist ground and water pressure.
http://www.hitachizosen.co.jp/english/pickup/pickup008.html
http://www.ncus.ntu.edu.sg/Events/Documents/SRMEG%20Seminar%...
The water table in Seattle is very high, about 4 feet in that area. So at the point of the blockage they are under 40 feet of water. Every ~33 feet of water is an extra atmosphere of pressure.
The tunnel is not filled with water though. See abduhl's answer for the correct response.
It seems they are under water!
They probably have an airlock behind the machine since I doubt the drill head itself is air tight against the walls.
Any bore holes would have to be water proof, or at least pressurized to keep them from filling up.
Let me answer.
"Chris Dixon, the project manager at Seattle Tunnel Partners [...] 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. " ~ The article.
Which is why there will never be a followup.
"Mystery Object Found to be Benign, Everyday Rock" does not make for a great headline.
Edit: I may be underestimating NYT's ingenuity a bit. I suppose "Big Bertha Resumes Drilling After Penetrating Ancient Glacial Super Rock" would serve the purpose.
"Subterranean Seattle Drilling Engineers Use This ..."
(wait for it)
"... One Weird Trick ..."
(ah, there it is)
"... To Conquer Ancient Mega Boulder Behemoth"
Yep. That's a headline.
Print news is now web-based which is all about ad impressions via alarmist or overly dramatized articles. Journalism somehow keeps finding a way to get worse.
The area that Bertha is digging in right now is glacial till, so it wouldn't be even a little surprising if it ran into a big glacial erratic. It should be able to chew through those even so, but if it ends up loose and just bounces around in front of the cutting head then it would be a problem, which is probably what's happening.
Also: why would the boring machine have trouble with some wood or stones of the size you'd use for walls in an old building?
> A secret subterranean heart, tinged with mystery and myth, beats beneath the streets in many of the world’s great cities.... Now Seattle, at least for now, has joined that exclusive club.
That lead is funny in light of http://en.wikipedia.org/wiki/Seattle_Underground
I thought the same. The old underground Seattle used to be a tourist attraction 40 or so years ago. What's new about this?
Still is. The Seattle Underground Tour is still one of those go-to tourist activities, like Pike Place Market and the Boeing Factory Tour.
> Tourists seek out the catacombs of Rome, the sewers of Paris
I think it's the opposite: the catacombs of Paris are quite famous (at least in France), and the ancient sewers of Rome are likely to be visited, since sewers are a Roman invention IIRC.
I got curious how the machine works and I found this video
http://www.youtube.com/watch?v=Dk-8Q42NCSQ
Pretty fascinating stuff.
Thanks for the video, I'm sure my kids will love watching it with me.
The one idea I had was wouldn't it be cool if they could somehow use the material they've cut through in the cement tunnel that they are building.
> "The object’s composition and provenance remain unknown almost two weeks after first contact"
Anyone else thought "Arthur C. Clarke" when reading this part?
I heard a choir of discordant voices, and pictured something smooth, rectangular and black.
A friend had never seen _2001_, so we watched it just last night. As I read I thought I heard Haywood Floyd's saying, "Its origin and purpose are still a total mystery."
I saw a smaller Rama buried under Seattle
> In October, workers walked through the first
> rings of the highway tunnel being built under
> Seattle’s waterfront toward the _boring_ machine
> called Bertha.
I haven't been able to tell from any reports yet. What is it about this object that they weren't able to discern existing through sonar/ultrasound/core samples/whatever pre-engineering I imagine these sorts of projects do? Is it that it's just so far down? Or do we not even know?
A couple things:
1. We generally do a boring every couple hundred feet along an alignment for tunnels. The bore hole is about 2" in diameter. You can imagine that we miss white a bit of subsurface detail. We rely on experience and local geological history for fleshing out the details and putting things in context. Sometimes we just flat out miss things. 2. Geophysics methods (sonar essentially) is not very good at telling you what something is past "hard", "soft", or "void". In a glacial till you get a lot of all three.
As a former Seattleite I think there is a decent chance this is just another one of restaurateur Ivar Haglund's futuristic adds like the Billboards for submarines [1]. Perhaps a literal acer of clams.
[1] http://seattletimes.com/html/localnews/2009889864_ivar18m.ht...
(the underwater billboards did turn out to be a Hoax/Stunt that were not actually put there in 1954.)
>> "I’m going to believe it’s a piece of Seattle history until proven otherwise," said Ann Ferguson, the curator of the Seattle Collection at the Seattle Public Library
It is exactly what my biases would lead me to believe it is, without evidence, unless you go to the effort to prove otherwise.
That's pretty harmless in this case, the necessity of getting though it means they will have to find out what exactly it is.
Perhaps 'hope' would have been a better choice of word.
There's nothing wrong with saying this. The problem is when you leave off the "until it's proven otherwise" part.
I am the only one seeing the paywall?
Headline: "Giant mystery object turned out being a banal paywall"
Don't worry, it's just linkbait. The article is two full pages of wild guesses on what they think is blocking it.
Open it in private browsing mode.
Maybe they've bumped into the last tunnel boring machine left behind by ancient space travellers :)
It is actually happening.
Reminded me of this episode of Star Trek:
https://www.youtube.com/watch?v=39roz9jQfzE
Uh-oh... oO;
Do the conspiradroids think it is a UFO yet ?
I hope it is an ancient alien space ship.