Construction has started on the tunnel boring machine launch pit for the WSDOT SR 99 Tunnel Project (Viaduct Replacement). The 420 foot long pit is being constructed using secant pile retaining walls, with 2 rows of 5 foot diameter piles, all around 90 feet deep. Based on the fantastic photos on WSDOT’s Flickr Page, it appears that Malcolm Drilling is performing the secant pile wall work. [Source: The Seattle Times via ASCE SmartBrief. Image: WSDOT Flickr]
The photo of this failed SPL wall is pretty remarkable. It was discussed in a thread I came accross on EngTips.com. The originator of the thread (kleo) says he was involved from the contractor side […]
This article describes the challenges faced by the World’s largest hard rock TBM (47.2-ft in diameter) as it tunnels through some very difficult geology while constructing a massive tunnel under Niagara Falls for hydroelectric power […]
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)
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