Bertha Stuck, Divers might be used...

[WaGigKpn]

So the Big tunneling machine is stuck under Seattle. It is 60' underground and they dont know what it ran into. I have heard on the news, and mentioned in this article http://mynorthwest.com/11/2412946/Offic ... ing-Bertha that they might need to use divers to inspect/remove the object. The area needs to be pressurized to keep groundwater at bay.

This brings up so many questions...on the radio this morning a spokesperson said they need a pressure chamber to pressurize the divers for an hour prior to working the site. They will then pressurize the cutting zone where the divers would enter and work. They would be limited to about an hour of work and then spend a couple hours in the decompression chamber.

Could someone explain how they are able to make a seal in the cutting head area to pressurize it? Seems like blow back around the cutting head/area would be a big issue. Also, why pressurize prior to entering the pressurized area?. Also, why are they limited to such a short time working in the pressure zone?

Very interesting situation at hand...

[Jeremy]

I had many of the same questions when this story came out

[YellowEye]

My Dad works in the tunneling industry. I'll ask him, but it might have to wait til the weekend.

[Norris]

Because Science....

[GearHead]

I enjoyed this take on the story:
http://m.seattle.curbed.com/archives/20 ... way-99.php

[mpenders]

Looks like the Bertha has a couple of hyperbaric chambers already incorporated into it. Not sure why they have to acclimate over an hour - maybe to prevent a rapid-descent type of narcosis?

[kdupreez]

Have these guys never seen War Of The Worlds!!

Dont disturb buried alien machines..

[LCF]

I was lucky enough to attend a lecture on decompression at DEMA. I can't remember the name of the presenter, who was from DAN, but he went on at length about decompression in modern tunneling, and apparently DAN has been consulting on the project in Seattle. Workers in the drilling rig are subject to the same decompression considerations that divers are, although they are not divers, in that they are not working in water. Why they take them an hour to get to 4ATA, I have no idea.

[H20doctor]

this is the company doing the diving.. my friend works in the tunnel

[Desert Diver]

I was lucky enough to attend a lecture on decompression at DEMA. I can't remember the name of the presenter, who was from DAN, but he went on at length about decompression in modern tunneling, and apparently DAN has been consulting on the project in Seattle. Workers in the drilling rig are subject to the same decompression considerations that divers are, although they are not divers, in that they are not working in water. Why they take them an hour to get to 4ATA, I have no idea.

I didn't see the pressure they would need to be at. Was it 100' equivelent? I suspected they put more pressure in there than the 60' depth for some reason??

[spatman]

I was lucky enough to attend a lecture on decompression at DEMA. I can't remember the name of the presenter, who was from DAN, but he went on at length about decompression in modern tunneling, and apparently DAN has been consulting on the project in Seattle. Workers in the drilling rig are subject to the same decompression considerations that divers are, although they are not divers, in that they are not working in water. Why they take them an hour to get to 4ATA, I have no idea.

I didn't see the pressure they would need to be at. Was it 100' equivelent? I suspected they put more pressure in there than the 60' depth for some reason??

The top of the machine is at 60', but the machine itself is almost 60' tall. So to the bottom of the tunnel currently is almost 120'.

[ljjames]

To keep the Bay at bay...

[LCF]

The graphic says 4ATA, which is where I got the number.

[Joshua Smith]

YES BUT HOW DEEP R THE GOIN 2 DOVE?

[Mortuus]

YES BUT HOW DEEP R THE GOIN 2 DOVE?

A millions billions

[Mattleycrue76]

Interesting. I was just talking to my neighbor yesterday. He is in the running to be one of the divers (the commercial diver/pile drivers union sued to make sure they would be awarded the job) to go down there. From what he was saying, they plan on more extensive shifts (similar to sat. diving). But then it hasn't happened yet. If he gets the job, it'll be interesting to get a first hand report.

[kdupreez]

any news on whats down there?

[Dusty2]

Mums the word. Guess they are still scratching their heads. You'd think that with all the hi tech in Seattle they'd have it all figured out by now.

[pogiguy05]

Maybe they finally found Jimmy Hoffa

[sitkadiver]

any news on whats down there?

I'm trying to not get too excited becuase there's a good chance it's just a bloody big rock. However, I have been looking at photos of the waterfront trying to determine what may have been filled over when they built the newer peirs. The Seattle public Library has a decent collection of historic photos:

http://cdm15015.contentdm.oclc.org/cdm/ ... 392/rec/18

[AdrianSmith]

any news on whats down there?

I'm trying to not get too excited becuase there's a good chance it's just a bloody big rock. However, I have been looking at photos of the waterfront trying to determine what may have been filled over when they built the newer peirs. The Seattle public Library has a decent collection of historic photos:

According to the most quoted article I've seen so far the drill bit is a full twenty feet deeper than the fill that was used (60' down vs 40' of fill). That means chances are it's NOT something from the early history of Seattle - if the article is correct it's just too deep below that layer.

-Adrian

[spatman]

any news on whats down there?

http://www.wsdot.wa.gov/Projects/Viaduc ... splay/1369