Wednesday, January 14, 2015

Another horrible tunnel job

Article



Sinkholes are always the tip of the iceberg of ground control problems when tunnelling.  You should be able to cut settlement to zero with a pressure-balancing tunnel boring machine, but that takes money.  Already houses are cracking, and they are complaining about vibrations.  This is going to be a darn train tunnel!

As well, the tiniest bit of settlement makes things a lot worse when the earthquake comes along.

Update:  My one comment of the year has me making an addition.  I will make up a totally fictional situation.

My company Cheapnsleazy Inc.  has just finished a tunnel that may rhyme with a certain blue pill.  I go to Vancouver, and impress them all with my astonishing low price.  I had changed the name because I made a billion on charging extras, and a few people might worry.  I get a crappy old boring machine and paint it up.  What me worry?  I charge ahead at full speed, running a huge ground deficit, with all the portals wide open.  The trees tilt and the buildings crack.  Not me!  Finally I run into big trouble when the sinkholes open up way in front of the machine.  Now is the time for my special trick.  I go to court -- "You didn't tell me that dirt was dirt!"  The judges always go for the contractor.  Another extra billion in the pocket.

Update2:  I am also yelled at because I'm not giving any information.  You will never get information!  The contractor makes a point of never hiring engineers, so he can go full blast with his Stupidity Defence.  And the government people are all under the control of the PR department.

3 comments:

Anonymous said...

How do you know they aren't using one? Most of these issues (and has been mentioned in several articles) comes into play when the machine needs to stop and depressurize for cutter head changing.

Harold Asmis said...

No way that all the shit comes pouring on a cutter head change. That didn't happen in London. Anyway, that should be easy-peasy now.

http://www.popsci.com/technology/article/2012-04/drill-dentists

Harold Asmis said...

Whoops, this is funny.

http://www.popularmechanics.com/technology/engineering/extreme-machines/americas-biggest-tunnel-boring-machine-is-stuck-beneath-seattle-16514815