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Object Blocking Giant Tunnel Borer Was an 8" Diameter Pipe
An anonymous reader writes "A few weeks ago we discussed news that a tunnel boring machine measuring 57.5 feet in diameter was halted underneath Seattle after running into a mysterious object. Project engineers have now figured out what the object is: an 8-inch-diameter pipe. In 2002, researchers for another project — the replacement of the Alaskan Way viaduct — drilled down into the ground to take water samples. They used the 115-ft-long pipe as a well casing. As it turns out, this well site was listed in the contract specifications given to all bidders for the tunnel's construction. In addition, the crew manning the machine noticed that it was chewing up pieces of metal, and they removed part of the pipe and kept going. Only later did they realize that significant damage had been done to the machine's cutting face. Officials aren't sure how long repairs will take, or how much they will cost."
Looks like somebody forgot to RTFM.
Even recent stuff tends not to be recorded in a nice way, like a computerized 3d model that can be used to keep all the data in one place and plan excavations. Instead it's often just a list of things in freeform text, like "well site at [lat,long], dug 2002, depth 115 ft". And older stuff is even less well documented; nobody really has an accurate map of what's under NYC.
10 PRINT CHR$(205.5+RND(1)); : GOTO 10
But it turns out that the boring machine found a boring object! (Why am I not surprised?)
Ezekiel 23:20
But for a $1.44B hole in the ground, I'd want to make damn sure every inch I dig through presents abolutely no risk whatsoever.
And how do you suppose they are to do that? The only real way to see exactly what is underground is to dig a hole. Sonar only gets you so far, records are sketchy and incomplete, at the end of the day the only way to be 100% sure there's nothing in the way of digging a hole is to dig the damn hole.
This was a fuckup, sure, but it's on the scale of "we hit something we knew we were going to hit (although not exactly where), we removed it when we hit it, but it turns out it fucked up the drill head when we tried to drill through it." I wouldn't bet on this causing the whole billion-dollar project to fail - it's most likely to be a couple hundred grand, maybe a few million in repairs. And that's coming out of the contractor's profits, not from the state, most likely.
Yo dawg, we heard you were digging a pipe, so we put a pipe in your pipe so you can tunnel while you tunnel.
#naabhaprzrag, #sverubfr-000, #agi-fcbafberq, negvpyr[pynff*=' negvpyr-ary-'] { qvfcynl: abar !vzcbegnag; }
The problem could be serious in terms of time and effort, though. The machine is meant to only go forward -- there is no reverse. Repairing the bits on the face of the machine will require excavating a large void in front of the machine just to create room for the repair work itself. That probably means old and slow classic mining techniques will need to be used.
And how do you suppose they are to do that?
In this case, it's just a matter of making a phone call. As in "Hello, Alaskan Way Viaduct project officials? This is STP. The DOT says you bore a hole in the ground in 2002. We're just calling to make sure you guys removed the pipe."
One quick phone call. Just like that...
I'm not saying each and every danger can be predicted in a project like that, but in this case, the hazard was known and could have been fully assessed.
Also, while all potential problems can't be avoided, at $1.44Bn, they should at least try their best to minimize them.
"A door is what a dog is perpetually on the wrong side of" - Ogden Nash
Yeah, that'll probably work something like this...
Welcome to Alaskan Way Viaduct customer support. Your call is important to us. We are receiving a higher than expected level of calls at the moment and thank you for your patience. You're approximate waiting time will be 30 minutes.
4 hours later
Pleased to be welcome to Alaskan Way Viaduct customer support, how may I help you?
"Hello, Alaskan Way Viaduct project officials? This is STP. The DOT says you bore a hole in the ground in 2002. We're just calling to make sure you guys removed the pipe."
Pleased to be sorry, sir, I do not know what you mean about DOT.
15 minute explanation later...
Pleased to be putting you through to my manager
2 hours later
This is Alaskan Way Viaduct level 2 support, how may I help?
"Hello, Alaskan Way Viaduct project officials? This is STP. The DOT says you bore a hole in the ground in 2002. We're just calling to make sure you guys removed the pipe."
The documentation states that the pipe has been removed sir.
Science advances one funeral at a time- Max Planck
I don't see this coming out of the contractor's fee. From local news reporting (I live in Seattle) this looks to me like the state is the up-gefucking party here, and if I were the state I'd be looking to avoid being sued by the contractor for providing misleading/incomplete information during the bid process. I expect that total cost of this little mishap will be well into the $1M+ range, and it'll come out of contingency money. Since we're still early in the dig process and haven't even gotten to the hard parts (digging under large buildings, for example) it's not good to be eating big chunks out of the contingency money at this point.
The problem is if there has been damage to the rest of the face, the support structure around the bits. This is not accessible while the machine is in operation, particularly for an earth pressure balance machine like they're using. (Required when there's lots of groundwater or a need to minimize surface disturbance, such as in an urban area.)
Yes, but was it an alien 8" pipe?
From TFA:
Chris Dixon, project director for contractor group Seattle Tunnel Partners, said the builders presumed there would be no pipe in the way, because casings are customarily removed after use.
When I dig in hole in my backyard, I may presume there's nothing in the ground. That's because if I hit a snag, my cost will be the price of the shovel.
But for a $1.44B hole in the ground, I'd want to make damn sure every inch I dig through presents abolutely no risk whatsoever. And since that's taxpayer's money, if I was Seattle resident, I'd sure as hell want to know who the fuck "presumed" stuff on my money...
Actually, if you're digging in your back yard with any sort of power tools, you should still call your local utility locating service first to make sure there are no gas lines or other infrastructure buried in your back yard.
You're probably safe digging with hand tools (there's usually a marker tape or cable above more recent pipes), but if you're using something like a pickaxe or hammering a rod into the ground, you really ought to check first or you may find yourself on the hook for expensive utility repairs if you don't end up blowing up you and your house first.
The "reforms" have been primarily to keep individuals from discharging debt while still allowing corporations to do so. That's why the left opposed it.
Did you even read the grandparent? The cutters can be replaced from inside the machine. If there is damage to the face, they may find it impossible to replace the cutters. The area where the cutter is located is under high pressure and inundated with water. Yeah, they can back it up, but that still leaves the pressure and water to deal with.
zosxavius photography
The tunnel that Bertha's digging isn't another project — the whole reason for digging the tunnel is to replace the Alaskan Way Viaduct. See here.
The wells were drilled in 2002 to study the ground after the 2001 Nisqually quake. But that's a related project, because the Nisqually quake is the reason why we got to thinking about a replacement for the Alaskan Way Viaduct.
Am I making sense? I hope I'm making sense. At any rate, the story summary needs updating.
That is a problem that is pretty unique for Germany and it is completely unreasonable to have a map of where all bombs were dropped over Germany while it is (or at least should be) completely reasonable to have a map of where cables and pipes are under a city.
It's a worldwide problem, there are unexploded bombs wherever there have been conflicts using them, and in training areas. Southeast Asia is particularly badly affected from American bombing.
http://en.wikipedia.org/wiki/Unexploded_ordnance