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Fixing a 7,000-Ton Drill 101

Posted by Soulskill
from the it's-probably-just-your-alternator dept.
An anonymous reader writes: At the end of last year, we discussed Bertha, the world's largest tunnel boring machine. During an effort to drill a viaduct beneath downtown Seattle, the machine — clocking in at 7,000 tons, 57.5 feet in diameter, and 326 feet long — got hamstrung by an 8-inch-diameter steel pipe. The complexity and scope of the repair plan rivals that of the project itself. "The rescue operation (workers call it "the intervention") began in late spring with construction on the shaft to reach Bertha. Workers have been sinking pilings in a ring to prevent the shaft from collapsing, using 24,000 cubic yards of concrete — enough for a medium-size office building. Once that ring is complete, digging on the shaft will start. When the shaft is ready, Bertha, which is damaged but still operational, will be turned back on so she can chew through the concrete pilings to reach the center of the shaft. There, the machine will rest on a cradle where workers can detach the front end and hoist it out." That detachable front end? It weighs about 2,000 tons by itself. The repair bill is estimated at about $125 million.
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Fixing a 7,000-Ton Drill

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  • by chaffed (672859) on Saturday August 02, 2014 @01:06PM (#47589663) Homepage

    Actually, something else is causing the seals to fail on the bearings and master bearing. The sampling pipe was the original theory but it could not account for the damage being done.

    FTFA “Contractors are not entirely sure what’s happening to the seals. They’re letting sand in, which is not good,” said Matt Preedy, deputy Highway 99 administrator for the state Department of Transportation (DOT). “Either you’ve got gaps somewhere, or you’ve got cracks in the seals.”

    http://seattletimes.com/html/l... [seattletimes.com]

    Basically, our water front soil make up is not ideal. Much of the Seattle water front is fill dirt from various late 19th century and early 20th century projects around Seattle. Much of the path Bertha is taking underground is lined with caissons to keep the liquid dirt at bay.

    • Actually, something else is causing the seals to fail on the bearings and master bearing. The sampling pipe was the original theory but it could not account for the damage being done.

      Even so, this shows what happens when you plan a one-shot operation with a single point of failure.

      In this case, two: the drill itself and the seals. Either one means failure. When it's a one-shot operation with no provision for pause or repair, you're SOL. Fixable in this case? Yeah. For a fortune.

      • by BitZtream (692029)

        125 million on a project like this is hardly a fortune.

        • by Anonymous Coward

          regardless to the size of the project 125 million is still a fortune.

        • Just an additional $250 per man, woman, and child in Seattle. You know, the people who get to pay for it... At least the minimum wage will bump to $15 per hour so those low-income families will get to see a good chunk of their supposed raise going to solve a problem that could have been avoided from day one...
          • by Megol (3135005)

            Strange mathematics given that this isn't a temporary project - it is an investment for the future of the city. When doing infrastructure projects one can't only think of the current situation but have to take the future into account. Most times infrastructure projects are founded by loans which means the costs are spread out over some generations of workers.

  • Steel pipe or drill rod?
  • Viaduct?? (Score:5, Informative)

    by markdavis (642305) on Saturday August 02, 2014 @01:13PM (#47589697)

    >"During an effort to drill a viaduct beneath downtown Seattle"

    Viaduct? How is digging/drilling a tunnel a viaduct? "A viaduct is a bridge composed of several small spans for crossing a valley or a gorge." http://en.wikipedia.org/wiki/V... [wikipedia.org] You cannot drill a viaduct.

    They are digging a TUNNEL under Seattle for a car highway as an alternative to an old, damaged viaduct.
    http://www.nytimes.com/2013/12... [nytimes.com]

    • Yes a car tunnel to be precise.
    • by Livius (318358)

      Via = road
      Duct = conduit.

      Nothing implies above or below ground.

      Though in this instance 'tunnel' would be a far more helpful description.

      • by Anonymous Coward

        dude, applying latin grammar rules to english doesn't make any sense.

      • by Anonymous Coward
        conduit = assembled
        im+ply = in + fold
        instance = urgent
        Sorry, I can't understand what your saying about an urgent tunnel, a viaduct being an assembled road, and why nothing is in folds.
    • Why a duck? Why not a chicken?
    • by Rinikusu (28164)

      What if they dig the tunnel, then build a lifted "bridge" viaduct inside this tunnel? WHERE IS YOUR GOD NOW?

      • by markdavis (642305)

        >" What if they dig the tunnel, then build a lifted "bridge" viaduct inside this tunnel? WHERE IS YOUR GOD NOW?"

        UG!!!! I can't handle such a possibility!

  • by Anonymous Coward

    Plasma digging robot trapped by ring of concrete pillars under Seattle.

  • Virtual tour (Score:5, Informative)

    by ian_po (234542) on Saturday August 02, 2014 @01:40PM (#47589793) Journal
    Whether or not Mitsubishi fucked up their cutter head bearing design, or Seattle Tunnel Partners forgot to read the documents that described the exact location of the previous exploratory bore pipe, regardless of if it's even possible to sucessfully extract the cutter head without sinking the current viaduct with all the additional excavation and ground water pumping, this virtual video flythrough [youtu.be] from four years ago is my favorite thing to come out of the project.

    And if you enjoy crappy flash web cam software, you can watch the current progress on the cutter head replacement shaft here [wa.gov].
    • Re: (Score:3, Interesting)

      by Anonymous Coward

      Perhaps Sealttle should take a lesson from the Crossrail project in London. There has been 3 * 1 hour long TV progs about the building of the tunnels recently broadcast.
      They were called "The Fifteen Billion Pound Railway".
      As a Civil enginner and having worked on the Channel Tunnel, I was amazed at the progress that has been made since the late 1980's in tunnelling. The bits where they had to thread the TBM between existing tunnels at Tottenham Court Road was fantastic.

      I'm sure the programmes are on the inte

    • David Macauley [wikipedia.org] did this decades [socks-studio.com] ago.

      • by ian_po (234542)
        Wow! Macaulay's Castle [wikipedia.org] was a favorite picture book growing up. But I don't think I ever read Underground :(
  • by Effugas (2378) *
    World's largest *unclassified* tunnel boring machine.
    • Bingo. There's anecdotal but nonetheless convincing evidence that far, far larger tunnel-boring machines are used to connect top secret, underground facilities...
  • ...Must be having to sell boring machines. I would try to save the situation by going humorous, with an ad series starring Ben Stein.

  • Most of these TBMs are left in place in an isolation tunnel to rust away once they've finished a job. Why not just get another TBM and scrap this one? It seems like they're going through a lot of work when the TBM is probably only worth 20 to 40 million to fix it.

    • by evilsofa (947078)
      This particular TBM cost $80 million:
      http://www.popularmechanics.co... [popularmechanics.com]
      They're spending $125 million to fix it. It seems plausible that dismantling it from behind and assembling a new one in place would have cost more than $45 million (plus $80 million for the new TBM).
      • by Virtucon (127420)

        Assemble a new one and cut through the old one then. It seems strange that a 7000 ton machine that cost $45 mil gets taken out of action by a pipe. It would seem to me that they'd make it a bit more repairable than this. Oh well, more money, more delays.

        • by Reziac (43301) *

          Someone explain to me how this is more cost-effective than drilling several smaller paths using smaller, more-proven equipment that costs a whole lot less both to buy and to repair? Seriously, I'd like to see the numbers.

      • It seems plausible that dismantling it from behind and assembling a new one in place would have cost more than $45 million (plus $80 million for the new TBM).

        At first I wondered why they were going to sink a shaft and tunnel into it with the degraded-but-working machine. Why couldn't they just expand the tunnel behind the machine using less automated digging methods, then back the machine up into the room to get access to the front of the machine to repair it?

        Then I looked a little deeper and discovered th

        • by Carnildo (712617)

          whatever is above them in downtown Seattle.

          Five city blocks (low-rise -- doesn't look to be anything over eight stories tall), a quarter-mile of the Alaska Way Viaduct, the entrance to the downtown ferry and water taxi docks, and two entrances to one of the larger docks at the Port of Seattle. If the tunnel is deeper than I think, or the soil is more liquid, add another seven city blocks (also low-rise), one park, the ferry docks themselves, part of the Port of Seattle dock, and maybe the football stadium.

  • Can't make your shit out of tungsten so when you hit a teensy 8-inch pipe you don't fuck the drill head up?

    They should be asking for a refund on their drill head. I've blown apart 8-inch pipes with 10 inch coring bits and did NOTHING to the bit, which itself was about 1/8th the thickness of the pipes inner walls.

    Mohs hardness scale, do you even, motherfuckers?

    • Can't make your shit out of tungsten so when you hit a teensy 8-inch pipe you don't fuck the drill head up?

      They should be asking for a refund on their drill head. I've blown apart 8-inch pipes with 10 inch coring bits and did NOTHING to the bit, which itself was about 1/8th the thickness of the pipes inner walls.

      Mohs hardness scale, do you even, motherfuckers?

      The cutting discs(Tungsten) and the head face(hardened steel) are hardened materials.
      The the cutting face was not damaged at all AIUI. It was the hea

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