This is an interesting video of crews changing cutterhead teeth on the Bertha TBM beneath downtown Seattle. [Source: WSDOT YouTube Channel. Image: YouTube]
Video: Changing cutting tools on Bertha TBM
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The tunnel liner that is being placed by the Bertha tunnel boring machine consists of precast concrete segments. This video by the WSDOT shows how they are made at the casting yard, and what Bertha […]
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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 […]
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12 Miles of Tunnels for D.C. Sewer
In Washington D.C., the D.C. Water and Sewer Authority (D.C. WASA) finalized a lont-term plan in 2002 aimed at reducing combined sewer outfalls into the Potomac River and its tributary, the Anacostia River. A major portion of this plan is a $2.2 Billion (US) deep tunnel program to handle excess stormwater flows and prevent the combined sewage from being discharged into the environment. Read on for a map and more info. (Photo of Anacostia River, by D.C. WASA)