Soil Sinking Around Big Dig Tunnel

BOSTON (CBS) – Engineers say a space has opened up under one section of a Big Dig tunnel, and they can’t fix it.

When engineers built the tunnel system, they froze the soil in some places, to keep it from collapsing.

But now the soil under one section of the tunnel is thawing, and a space is opening underneath.

In parking lot along the South Station train tracks you can see can see the buckling, an impact of the sinking soil around the Big Dig tunnel below.

WBZ-TV’s Karen Anderson reports

Wednesday, the Acting Highway Chief Frank DePaola briefed the MassDOT board on the problem.

DePaola said, “While some ground settlement was expected, the thawing of the frozen soil during the past nine years, has resulted in greater settlement than we originally predicted.”

When the I-90 tunnel was built, engineers froze the ground around South Station to stabilize it. They froze it 200 feed wide by 160 feet long by 130 feet deep.

Now, as it’s melting, the clay soil is settling twice as much as engineers expected, leaving a void below the I-90 connector tunnel. It’s a hole filled with water, and they don’t know how big.

“We don’t think it’s serious at all, it’s another issue that we have to monitor,” says DePaola. “So far there has been no indications of stress or strain within the tunnel sections itself.”

DePaola says the tunnel has not been affected by soil problems, in part because it was built to act as a bridge.

But a major water main pipe was affected. It sunk eight feet and had to be replaced at a cost of 1.2 million dollars. That happened several years ago.

Incoming Transportation Secretary Richard Davey says the tunnels are safe.

Davey says, “We would not be letting cars go through there or more specifically trains over those tracks if there was any issue whatsoever.”

  • A

    Still trying to understand why we in this state actually have to file Income tax.

    Wouldn’t it be easier just taking the money outside and then put a match to it ?

    You freeze something and unless you keep it cool, it will thaw

    But no, apparently putting a tunnel section on top of it will prevent the laws of physics from taking place

    But thankfully, the transportation secretary assure us that the tunnels are safe. Of course aside from falling slabs crushing cars, falling lights and now the surrounding soil holding the tunnels up, melting away

  • eddwal50

    what about the train tracks how are they affected by the thawing soil

    • A

      I wouldn’t worry about it. Don’t forget…

      “We don’t think it’s serious at all, it’s another issue that we have to monitor,” says DePaola. “

  • emom

    IT’S MELTINGGGGGGGGGGGGGGGGGGGGGGGG,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

  • Ballerina

    Thanks for the warning!! That’s to be expected with the colossal goat f*&# that the Big Dig developed into. These companies involved with the whole project should be incarcerated deep into the worst prison that Mass has!!!!!! Someone made some big $$$$$$$$$$$ on this boondoggle!

  • Tee Kay

    IYa right, it’s safe – until the disaster comes.

  • Willow

    I wonder how many times a day those same engineers use the tunnel themselves. They must think we’re all fools, or just plain stupid if we believe any of that tunnel is safe.

  • joey

    what a shame: Ronald Reagan vetoed this project and it got overriden!!!!!!!!!!!!!!!!!!

  • jaygee

    I have a very strong feeling that if Tip O’Neil was still around, he would take his name off that boondoggle in a New York minute. While I admit that I love using the results of the Big Dig, the corrupt practices by many companies involved, a complete lack of oversight and total mismanagement of the entire project can only make you wonder how they ever built the pyramids without benefit of “20th century ingenuity”.

  • Mark

    Another gift from Ted that keeps on giving.

  • Transportation Notes: Future MBTA Fare Hike? « CBS Boston

    […] the ground settlement around South Station affecting the railroad tracks near the station causing a potential void beneath the I-90 connector tunnel base slab. Ongoing inspections have not shown any signs of excessive stress in this area of the Big […]

  • JohnC

    You mean that you actually expect decent quality in a $15 Billion government project?

  • Adi

    “They froze it 200 feed wide” may it is time to double check the spelling. 200 feet wide not “200 feed wide”.

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  • Rep. Lynch Requests Inspections Over Tunnel Soil Problem « CBS Boston

    […] (CBS) – Calls have begun for new safety inspections after WBZ-TV broke the news that the Big Dig soil around the I-90 connector tunnel that was frozen during construction for stability, is now sinking twice as quickly as engineers […]

  • R

    It acts as a bridge. It doesn’t affect the tunnel strength if a small section of soil is settling. They expected it to thaw and settle, its just settling more than expected. If they didn’t actually believe it wasn’t safe, they wouldnt risk their behinds to pretend it was.

  • MassDOT To Manage Issues Like Big Dig Leaks ‘As They Arise’ « CBS Boston

    […] above in a parking lot along the South Station is the buckling pavement and fence: signs of the sinking soil around the Big Dig tunnel below that 50,000 commuters use […]

  • Minnie Osullivan

    Nice blog, thank you! I really love it!

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  • Eberly

    Soil Sinking Under Big Dig Tunnel In Boston

    private and public} clients. […]

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