The area is approximately 300-m from the Rhine River, and groundwater is very shallow. As noted in another NCE article, the contractor constructed 15 dewatering wells when only 4 were approved. Additionally, the pumping rate being used was 750 m^3/hr, or nearly double the 450 m^3/hr it was pumping in December of 2008. Clearly the groundwater is one component of the failure, but it does not appear that there is sufficient evidence to say exactly what role of the groundwater was or if the shoring walls did in fact fail and lead to the collapse of the Cologne historical archives and the deaths of two people.
[Updated November 17, 2009] A few new posts from Ontario-geofish [/Updated]
Those with interest in rock mechanics and tunneling might be interested in this project. The Ontario Power Generation (OPG) company is the owner of a $600M (Canadian) construction project to create a third hydro power tunnel under Niagara Falls. Apparently the project is having all kinds of problems with overbreak in some very difficult tunneling conditions which means very slow progress and big $$ overruns. (Photo from niagarafrontier.com)
I’ve been meaning to post something on this project for some time. I admit that my perspective is biased by the viewpoint you can find on the Ontario-geofish blog. I’ve mentioned Harold Asmis before, he’s the owner of the OG blog, and a former OPG employee if I understand correctly. He left OPG for a career doing geophysics and earthquake engineering for the Nuclear Power industry in Canada. I highly recommend his blog, he has great insight into tunneling, earthquakes, siting of nuclear power plants not to mention opinions on all kinds of other things. His writing style is very colorful and entertaining as well.
So, Harold has written a whole series of blog posts on the Niagra Tunnel project, including a 5-part series entitled "The Disaster of the Niagara Tunnel" and a 4-part series called "Niagara Tunnel: doing it Right". He is not directly involved with the project, but his long career with OPG and related disciplines gives him some great insights. I’ve collected a list of some of his blog posts on the Niagara Tunnel project as well as a few other links about the project. Click through for the good stuff.