Under Seattle, a Big Object Blocks Bertha. What Is It?

[WarToad]

http://www.nytimes.com/2013/12/20/us/under-seattle-a-big-object-blocks-bertha-what-is-it.html?_r=3&hp=&adxnnl=1&adxnnlx=1387533627-YlNMnV8Pt6kNSnu6ETcNtw&

Under Seattle, a Big Object Blocks Bertha. What Is It?

December 19, 2013
By KIRK JOHNSON

SEATTLE — A secret subterranean heart, tinged with mystery and myth, beats beneath the streets in many of the world's great cities. Tourists seek out the catacombs of Rome, the sewers of Paris and the subway tunnels of New York. Some people believe a den of interstellar aliens lurks beneath Denver International Airport.

Now Seattle, at least for now, has joined that exclusive club.

Something unknown, engineers say — and all the more intriguing to many residents for being unknown — has blocked the progress of the biggest-diameter tunnel-boring machine in use on the planet, a high-tech, largely automated wonder called Bertha. At five stories high with a crew of 20, the cigar-shaped behemoth was grinding away underground on a two-mile-long, $3.1 billion highway tunnel under the city's waterfront on Dec. 6 when it encountered something in its path that managers still simply refer to 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," Chris Dixon, the project manager at Seattle Tunnel Partners, the construction contractor, said in an interview this week. 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.

"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, who said she held out hope for something of 1890s Klondike Gold Rush vintage, when Seattle became the crazed and booming gateway city to the gold fields of Alaska and Canada.

At the downtown storefront museum for the tunnel project, called Milepost 31, visitors are cracking Jimmy Hoffa jokes or spouting theories about buried train engines. Gabe Martin, a sales clerk at a curio shop near the dig site, said he was intrigued by the Prohibition era, when Seattle rode a tide of illegal alcohol smuggled from Canada, and people had reason to bury things, not wanting them found. "Bootlegger stuff," he said.

Mr. Dixon said that efforts to drain water and reduce pressure at the drill head, with a series of bore holes pushed down in recent days, could allow workers to get safe access to the blocked site as early as Friday. But working at atmospheric pressures similar to what a diver would experience, the team could stay down only for short periods, he said, and each visitor would then need time in a decompression chamber.

And there is something of a John Henry's hammer theme to the tale of Seattle's object. Bertha is blind as a mole in front, with no forward-facing windows or cameras, so a kind of spacewalk through air-locked doors is required to get to the front of the machine for inspection. And the removal or breaking up of the object is likely to be done with jackhammers or other old-fashioned tools that a tunnel-digging sandhog worker of generations past would recognize.

If the object can't be broken up below ground, there would need to be excavation down from the street. In any event, Mr. Dixon and other state managers said, the machine's forward progress could be halted for weeks — though they stressed that work is continuing on the ends of the tunnel, and that it is too early to talk about cost overruns or delays. The tunnel is scheduled to be open to traffic by late 2015.

The tunnel is to run north and south along Elliott Bay from Century Link Field, home of football's Seahawks, to a point near the Space Needle on the north, allowing demolition of an elevated roadway and improved crosstown foot and bicycle access.

Economics and geology — two key threads of Seattle's creation — underpin the tunnel's impetus. Planning for the project began after an earthquake in 2001 revealed seismic vulnerability in the elevated viaduct roadway, which was built in the 1950s. Businesses and real estate interests were then sold on the idea that a tunnel, replacing the viaduct, would open access between downtown and the waterfront.

But unlike, say, Boston or New York, where tunnels are common and bedrock is close to the surface, getting to that end point is messy. Seattle's underbelly is more like pudding than soil — a slurry of sand, gravel and clay, all jumbled and compressed by the pressures from a 3,000-foot-thick ice sheet that extended as far as Olympia, 50 miles south. A city famous for being wet also has a high water table, only about four to five feet down.

And because Seattle, as first encountered by European-American settlers, was hardly conducive to being a city at all, with steep, glacier-carved hills rolling right down to the water, the landscape was reshaped from the beginning, with projects to grind down the hills. That in turn created lots of landfill, which went into the waterfront to level it and create land on which the city's commercial center rose.

"It's mind-boggling how much we have altered the landscape of Seattle," said David B. Williams, a geologist and author of a coming book about the making of Seattle's landscape, called "Too High and Too Steep, Reshaping Seattle's Topography."

"The tunnel is just a continuation of that story," he said as he walked north of downtown, where a cliff face showed the layered strata of the geologic past.

Mr. Williams, who blogs about local geology, speculated in a recent post that the remains of a famous shipwreck, the Windward — which foundered in 1875 and was buried near the waterfront — might be the kind of object that Bertha encountered, though he conceded that the machine could probably grind through a wood vessel as though it were paper.

In the end, he said, state engineers are probably right. A rock, huge in size or in a configuration that the machine cannot quite get purchase on to grind, is the most likely culprit. "I do hope it is not," he said. "It would be great to find some new mystery."

[Norval]

Oh ! ! They found my old van I parked back in 69.  Thanky 

[PLAYSWITHMACHINES]

Maybe they found "The Thing"

Maybe THIS will interest you, it scared the carp out of me when i saw the original movie.....

Enjoy!

[robomont]

One person said that area was actually backfill and he thought it was an old train engine.that would be a pain to cut through.probly end up with a big wad of metal stuck to the cutting head teeth.

[PLAYSWITHMACHINES]

I think you may be right, Robo mate
But those TBM's are pretty strong....we made a car smashing machine for a big scrap company, we figured the best way to deal with hard lumps of steel like engines, gearboxes etc, was to hit them with hammers. We had a huge roller with flailing hammers on it, dozens of them.

These would smash the entire car into small pieces about the size of a pack of ciggies.. 
Sometimes there would be an LPG tank, or an old camping gas canister in the car, and then,,,BOOM
Later, we found half-ball-bearings embedded in the C100 steel hammers, when we took it apart for a refit...

Imagine the force needed to do that

ETA; Why the hell they can't just fit a few titanium tubes in the front (with a cleaning mechanism or an iris-type shutter) i don't know.
Then they can poke a fibre-optic camera (called an endoscope, you can buy them in toolshops)down the tube & take a look outside, why they never did this, we will never know.
A typical example of the engineers having their heads up theis arses

[Shasta56]

I hope it at least turns out to be something interesting.  I'm working on clearing a paper jam in my printer.  So far, I found my missing PetPerks card from PetsMart.  Who knows what else the cats threw in there?  I really need to get a dedicated computer and printer space. 

Shasta

[WarToad]

http://blogs.seattletimes.com/today/2014/01/whats-blocking-bertha-a-huge-steel-pipe/

A buried steel pipe is mostly to blame for stopping the giant tunnel-boring machine Bertha, which has been stuck since Dec. 6 along the Seattle waterfront near South Main Street.

The long pipe was an 8-inch diameter, 115-foot-long "well casing," used to measure groundwater during studies in 2002 on the Alaskan Way Viaduct replacement project, project officials said.

Matt Preedy, the deputy project administrator for the state Department of Transportation, said he had no estimates about how much time and money it will take to remove the rest of the pipe and to repair damaged cutting tools on the face of the machine.

Nor does the team have a strategy yet for how removal should take place. One possible method is to send tunnel-trained divers to work near the cutter face, under extreme pressures that are exerted by groundwater.

The well site was listed in reference materials provided to bidders as part of the contract specifications, DOT says. "I don't want people to say WSDOT didn't know where its own pipe was, because it did," said DOT spokesman Lars Erickson. However, 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.

Dixon said the tunnel-machine crew first noticed metal pieces in Bertha's conveyor system in early December  — when Bertha's rotation actually shoved a segment of pipe through the surface, prompting crews to remove a 55-foot-long piece. However, the machine kept grinding forward just fine, Dixon said, leading STP to have what he called "a false sense of security" that things would be OK.

But then on Friday night, Dec. 6, the cutting face rotated without catching soil. The team later found unusual damage to cutting teeth, and then on Thursday night an inspection found a pipe fragment jutting through spaces between spokes of the cutter.

A modern tunnel machine can chew through dirt and concrete, but not steel. Even fiberglass rods caused a snag that delayed work several days this summer. Steel could become tangled in the spokes of the rotary cutting head, and in a conveyor screw that pushes dirt from the cutter face onto a belt that moves out the rear of the machine. Dixon said Friday that "we don't know" yet whether any moving parts are jammed.

Downtown Seattle contains some of the most frequently poked and studied ground on earth, which makes the blockage all the more confounding. Five-foot diameter holes were drilled alongside the tunnel path to install concrete pilings that protect the old viaduct; the contractors have used ground-penetrating radar; and geotechnical experts drilled test holes, which didn't hit this particular object.

For the last four weeks, DOT didn't mention the pipe during several news interviews and press conferences. Asked about this, Preedy said Friday that initially, the project's expert-review team thought the pipe was a secondary issue, and that a giant boulder seemed more likely. At 60 feet down, the top of Bertha is in glacial soil, beneath the extent of fill soils and debris that early Seattle settlers dumped near Elliott Bay.

The $1.44 billion tunnel construction, from Sodo to South Lake Union, is about three months behind schedule. But Bertha in November was advancing as fast as 50 feet a day, prompting Preedy to say it's possible to regain time after the steel is removed.

[micjer]

Thanks for the update.  I didn't figure that they would find an Alien Base or UFO.  Who comes up with these ideas?

If the Subterrene (Atomic) tunnel-boring idea hadn't been shelved, they could have used it to do this tunnel.  It would have gone through the steel well casing in no time.

http://atomic-skies.blogspot.ca/2012/07/those-magnificent-men-and-their-atomic.html

[WarToad]

I suspect there's a Project Manager(s) getting canned over this.  The contract specs covered the exact location of the tunnel, all previous property construction paperwork should have been pulled and reviewed for all the property along the specs.  Multi-million $$$ f-up is lost time and possible equipment damage.  Seattle taxpayers bend over.

[zorgon]

Thanks for the update.  I didn't figure that they would find an Alien Base or UFO.  Who comes up with these ideas?

Ummm LA TIMES? 1972?



http://www.thelivingmoon.com/45jack_files/03files/The_Tubes.html


Who says it was shelved? 'shelved' is a code term for 'gone black'

[zorgon]

Riddle me this Batman....


Most granite is made of quartz and feldspar. Granite is the common metamorphic rock that these machines tunnel through

Granite is made of three basic materials... mica, quartz and feldspar

Feldspar has a hardness of 6

Quartz has a hardness of 7

Each number is twice as hard as the number before

...yet these machines chew that up like its cornflakes

Iron has a hardness of 5.2  Steel a little higher at 5.5 -5.7


SO..

WHY would an iron pipe only 8 inches in diameter stop one of these?



I mean the sheer weight of the machine would snap it like a toothpick

Come on  People   

Think

[Ellirium113]

The long pipe was an 8-inch diameter, 115-foot-long "well casing," used to measure groundwater during studies in 2002 on the Alaskan Way Viaduct replacement project, project officials said.

This must be a screw up...an 8" heavy wall pipe would be insignificant to a machine this size. It would chew it up like a gummy worm. Perhaps they meant it was 8" thick well casing? That might be a slightly different story. Either that or this thing is just a huge coffee grinder good for mulching sand and dirt. Even if it DID damage some of the rolling cutters it would have been chewed through by the hardened cutting teeth. The soft-dirt tunnel boring machine pushes along @ 7 Bar hydraulic pressure, this one should be significantly higher.

[robomont]

Well casing pipe is like one to two inch thick wall pipe.but i agree that machine should munch through it.

[The Seeker]

Somebody is full of feces; I used to work for a well drilling company many moons ago... the roller cone bits we used for dirt and soft rock would rip right thru an iron or steel pipe, seen it happen too many times... those concrete cutters would not even notice that pipe was there...





seeker

[Sgt.Rocknroll]

I'm a piper by trade...that machine wouldn't have noticed that pipe even existed...Dumbazz yankees...lolololollll....