Blue Plains tunnelling completed27 July 2015
USA - The TBM mining the 4.5-mile-long Blue Plains tunnel completed her dig earlier this month and on Thursday, July 23 her cutterhead was extracted from a 100ft-deep shaft near DC Water’s Main Pumping Station in Southeast Washington, DC Water announced yesterday.
"This is a terrific milestone for DC Water's Clean Rivers Project," said DC Water CEO and general manager George S. Hawkins. "We are fortunate that the tunneling went so smoothly, finishing on time and on budget, and I applaud our DC Water staff as well as Traylor Skanska Jay Dee and everyone else who took part in this successful dig."
The JV launched the TBM in July 2013, from a starting point at the Blue Plains Advanced Wastewater Treatment Plant, tunnelling along the Potomac River and crossing under the Anacostia River. Carlton Ray, director of the DC Clean Rivers Project said the TBM performed as well as projected, "having a one-day best mark of 150ft. In her best week, she tunneled 631ft. This TBM's success means we are one step closer to a cleaner Anacostia River."
The Herrenknecht machine built the southernmost segment of the Anacostia River Tunnel. The next section will be mined by another TBM launching at a site near RFK Stadium. The Northeast Boundary Tunnel is the longest portion of tunnel, and that contract has yet to be awarded. At the northern tip of the tunnel system is the First Street Tunnel, a relatively short tunnel.
The Blue Plain TBM removed approximately 1.2 million tons of material that she mined. This was hauled away in nearly 72,000 truckloads over the last two years. She built the tunnel with 28,189 pre-cast concrete segments which made up 4,027 full rings.