In early July, 2015 Herrenknecht TBM Lady Bird completed the 7.24 km-long Blue Plains Tunnel that will be used to help improve the water quality in the Anacostia River in Washington DC, US. Blue Plains is the southernmost segment, the first portion of the proposed 20.92 km-long Anacostia River Tunnel.

On 23.07.2015 the cutterhead was extracted from a 30.48 m-deep shaft near DC Water’s Main Pumping Station in Southeast Washington, DC.

Lady Bird began boring in July, 2013 from the Blue Plains Advanced Wastewater Treatment Plant, along the Potomac River northward to Poplar Point and then crossed under the Anacostia River and continued west, finishing at a deep shaft along Tingey Street, SE. Average advance was 45.72 m/day, with a best week of 192.33 m. Some 1.2 million t of muck was hauled away in nearly 72,000 truckloads. The tunnel lining consumed 28,189 pre-cast concrete segments, which made up 4,027 full rings.

The next section from RFK Stadium will be mined by another Herrenknecht TBM, named Nannie. Dimensions of this machine are length 106.68 m, weight 1,248 t, cutterhead diameter 7.92 m.

The contract for the 8.23 km-long Northeast Boundary Tunnel, the longest section of the project, has yet to be awarded.

At the northern tip of the tunnel system is the First Street Tunnel, length 822.96 m, diameter 6.25 m, to be mined by TBM Lucy, weight 1,582 t, cutterhead diameter 7 m. This tunnel is designed as a flood protection project for the Bloomingdale and LeDroit Park neighbourhoods. The cost of TBMs is included in each contract, so they are owned by the contractors.

Click here for a video, here and us/109 for tunnelbuilder archive. Visit http://www.dcwater.com . 31/15.