Tunnel Business Magazine

OCT 2018

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As a milestone in the procurement process for the Hampton Roads Bridge- Tunnel (HRBT) Expansion project, the Virginia Department of Transportation (VDOT) announced Aug. 2 that the proj- ect will move forward with the bored- tunnel construction method to deliver the next connection across the Hampton Roads harbor. Both competing teams – Hampton Roads Capacity Constructors and Hamp- ton Roads Connector Partners – notified VDOT they selected the bored-tunnel method as the basis for their bid propos- als, which will be submitted in late 2018. "The selection of a bored tunnel means Hampton Roads will see some of the world's most sophisticated tunnel tech- nology at work. Once complete, this new crossing will greatly improve accessibil- ity, transit, emergency evacuation, and military and goods movement along the I-64 corridor," said VDOT Commissioner Stephen Brich. Although the immersed-tube method was used to construct all 10 of Hamp- ton Roads' existing crossings – from the original Downtown Tunnel in 1952 to the unnel in 2016 – recent technology advances have now made bored tunnels feasible in the region's soft soils. The Parallel Thimble Shoal Tun- nel, currently under construction at the Chesapeake Bay Bridge-Tunnel (CBBT), is also being built as a bored tunnel for the Chesapeake Bay Bridge-Tunnel Commis- or the CBBT will be 42 ft in diameter. The project represents VDOT's first bored tunnel. In addition to HRBT and the Thimble Shoal project, other bored roadway tunnels in the United States in- clude the P unnel and the Alaskan Way Viaduct Replacement in Seattle, Washington. The HRBT Expansion project will build a new bridge-tunnel adjacent to the exist- ing HRBT and widen the four-lane seg- olk to ease daily congestion between the Pen- insula and South Hampton Roads. The project cost is estimated between $3.3 and $3.8 billion. Bored Method Selected for Hampton Roads Bridge-Tunnel Project TUNNELINGONLINE.COM TBM: TUNNEL BUSINESS MAGAZINE // OCTOBER 2018 1 0 TERRATEC TBMs Progressing on Mumbai Metro In early August, TERRATEC celebrat- ed the assembly of its fifth new 6.68-m diameter dual-mode hard rock Tunnel um o's Line 3 project in India, at the CSIA International Airport shaft on contract UGC-06. The first four of these machines are now fully up and running on two other contract pack- ages (UGC-02 and UGC-05) and achieving production rates of up to 91 m per week, despite still being within the 'learning curve' period of their initial drives. The versatile TERRATEC single shield e equipped to operate in either Open or Closed mode in the predomi- nantly fresh and slightly to moderately weathered Basalt and Breccia that are anticipated on these contracts. The ro- bust hard rock cutterheads are mount- ed with heavy-duty 17-in. disc cutters, which are interchangeable with ripper tools, and feature large bucket openings that provide a 10% opening ratio. Other state-of-the-art features include 2,000-kW electric variable frequency drives that allow the cutterheads to cut efficiently in harder rock zones at maxi- mum speeds of 7 rpm and deliver an ex- ceptional torque of 8,000 to cope with more fractured zones of ground along the alignment – as well as active shield articulation and built-in two com- ponent backfilling grout systems. "Four of the sev e now in operation and they are achieving regular advance rates of 15 m per day on Package 2 and Package 5," says TER- RATEC Site Opera , Bill Brundan. "The machines are perform- ing very well, accomplishing combined production rates of over 40m per day, e now being assembled. By the end of the year all seven machines – including two 6.61 m diameter mixed/rock Earth Pressure Balanc e expect- ed to be mining simultaneously on all three contract Packages." Two of the 6.68-m diameter dual- mode hard ro are being used by the Hindustan Con- struction Compan c o- stroy JV to build the twin tunnels on the line's 4.049-km UGC-02, which was awarde um o Rail Corpora CL) in July 2016. Both machines were deployed from the Chhatrapati Shivaji Terminal ( launch shaft and are currently mining umbai Central Station eceiving shaft. The other three new TERRATEC dual-mode hard ro e being used by the J. Kumar – China Railway ering Group JV for the ex- cavation of sections on the line's 4.94- km contract UGC-05 (Dharavi Station – CSIA Domestic Airp eceiv- ing shaft) and 4.45-km contract UGC-06 (CSIA Domestic Airp eceiving shaft), which were also awarded last July. B U S I N E S S B R I E F S

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