Every tunneling machine needs its cutting tools replaced every now and then. But the challenge is keeping a giant machine sharp while a wall of waterlogged earth looms in front. Welcome to the world of hyperbaric interventions, where crews used compressed air to stabilize the ground and safely complete this high pressure work. This video takes you 200 feet underground for a rare look at hyperbaric work inside Seattle’s SR 99 tunneling machine, Bertha. [Source: WSDOT YouTube Channel. Image: YouTube]
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Rising Costs and Delays in Seattle Area Wastewater Plant and Tunnels
In keeping with our theme of rising costs on tunnel projects, the Brightwater sewage-treatment plant and treated waste pipeline project in King County Washington (Seattle area) is now up to at least $1.84 billion according to the lead consultant on the project. The treated waste pipeline is 13 to 14-miles long and at depths of 40 to 440-ft! It is being constructed nearly entirely by TBM. One source of delay was due to a tunneling subcontractor not being able to get parts (ball bearings?) because they were all being requisitioned by the US War Department for use in military equipment in Iraq and Afghanistan. Click through for information sources and links.
New Water Supply Tunnels Underneath New York City
Urban miners have been busy constructing a new water supply tunnel underneath New York City to supply the megalopolis with the water it needs. The miners, or sandhogs as they are known, are about halfway complete with the new tunnel which is expected to be in service by the year 2020. Work on the 60-mile tunnel began in 1970 and the total projected cost is $6 billion and is widely regarded as one of the most complex public works projects in the western hemisphere. When complete, it will help deliver 1.2 billion gallons DAILY to 8 million New Yorkers. The city currently gets its drinking water from two water supply tunnels that were constructed in the early 20th century and have not been inspected or repaired since then. More after the break. (Image credit History.com)