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Anacostia River Tunnel, Division H

SE Washington, DC<br style='line-height:2px'>DC Water

The District of Columbia Water and Sewer Authority (DC Water) is implementing its $2.6 billion long-term control plan for combined sewer overflows (CSOs), known as the DC Clean Rivers Project (DCCR). The DCCR is comprised of 20 miles of 23-foot-diameter tunnels at depths from 50 to 160 feet. The system will capture CSOs and convey them to the Blue Plains Advanced Wastewater Treatment Plant, the largest such facility in the world, treating more than 330 million gallons of sewage per day.

The Anacostia River Tunnel (ART) section, the second tunnel of the deep tunnel system, will convey CSOs along the Anacostia River in southeastern Washington, DC. HAKS is a member of the consultant construction management (CCM) team providing inspection services, including tunnel and near-surface construction, for the $250 million design-build project. The ART is a 23-foot-diameter by 12,500-foot-long tunnel to a depth of approximately 100 feet. It includes a 110-foot-long Inter-Shaft Connecting Tunnel (ISCT), six deep shafts and three tunnel-adits, which will be constructed using micro-tunneling. The ISCT will be constructed using the sequential excavation method (New Austrian Tunneling Method).

The ART will intercept the BPT when the tunnel boring machine (TBM) reaches the Poplar Point Junction Shaft. The TBM is mining predominately in soft ground using an earth pressure balance shield. The progressive installation of the cast-in-place liner in the CSO 019 south shaft will support the TBM launch, which will also utilize the space provided by the construction of the ISCT.

Team members are working closely with the design-build team to ensure that the underground works are constructed under strict quality assurance (QA) guidelines. Routine QA inspections include slurry wall installation and deep shaft excavation; shaft waterproofing installation; cast-in-place shaft concrete lining installation; and precast steel fiber-reinforced concrete lining installation.