This article is 4 years old, written before the tunnel project started, but it clearly lays out the risks. Not only in building the actual tunnel, but also that the city of Seattle (of which I'm a happy resident) is on the hook for any cost overruns. http://www.thestranger.com/seattle/what-could-possibly-go-wr...
Search for the section that starts with "The tunnel-boring machine gets stuck" to read Dominic's assessment of TBM risks.
Search for the section that starts with "The tunnel-boring machine gets stuck" to read Dominic's assessment of TBM risks.