Braintree Weymouth Tunnel
ot far from the Fore River Ship Yard in Quincy, a 26-by-35-foot access shaft leads down below the ground - some 200 feet down, to be more precise - to Modern Continental’s Braintree/Weymouth Tunnel job. At the bottom of the shaft, crews are working on a three-mile long tunnel that will eventually be used for wastewater systems maintained by the Massachusetts Water Resources Authority.
Work began on this project began with initial excavation and the construction of supporting slurry walls in June 1999. The tunnel, which is 11.5 feet in diameter, will stretch from the ship yard to the Inter-Island Tunnel at Nut Island in Quincy. Won on Modern’s bid of $73 million, this contract is part of the MWRA’s $150 million sewer relief plan aimed at improving systems in Braintree and Weymouth.
 
Two techniques are being used for this project. About a fifth of the tunnel will be constructed through the "drill-and-shoot" method, where crews place explosives in pre-bored holes in the rock and blast their way through. The remainder of the tunnel, some 12,000 linear feet, is being excavated a Wirth tunnel-boring machine. Work also includes two support shafts and a main access shaft. Steel rib support will be required to supplement rock bolts.
 
The tunnel, when finished, will support two new 42-inch wastewater pipes for the MWRA. It will also contain two 14-inch diameter sludge lines running from Nut Island to the fertilizer plant near the ship yard, which will eliminate the barging of sludge across Boston Harbor. Two 12-inch pipes will also transport water from the fertilizer plant to the tunnel, eliminating two million gallons of wastewater per day from the local sewer systems. Lastly, a new 12-inch water pipe will be installed to support a new pump station in Weymouth.
 
back
Construction  |  Residential Development
Commercial Development  |  Marine Services
Property Management  |  Architectural Services
Companies  |  About Us  |  Contact
Press Releases  | Site Index    

 
© 2002 Modern Continental Companies, Inc. All rights reserved.