Over 200 buildings will receive some form of geotechnical and geostructural monitoring around the Highway 99 tunnel in Seattle, better known as the tunnel that will replace the Alaskan Way Viaduct. A Seattle Times article listed some of the technologies being employed, such as automated survey machines, crack meters, extensometers, tiltmeters, liquid level sensors, inclinometers and crack gauges. A total of roughly 700 devices will be deployed by the time the tunneling starts this summer, a $20 million program. The project team will also be using interferrometric synthetic aperture radar or INSAR techniques to supplement the traditional surveying methods as they watch for subsidence and ground loss problems along the tunnel route. This satellite-based method is accurate up to 1/8 inch, but has the advantage of being able to cover a larger area than just using the survey prisms at particular points. [Source: The Seattle Times via ASCE SmartBrief. Image: KEN LAMBERT / THE SEATTLE TIMES]
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Niagara Tunnel – Crappy rock, Horizontal stress, SLOOOOOW progress
[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.