DESIGN AND CONSTRUCTION OF 86TH ST. STATION ROCK CAVERNS IN NEW YORK

摘要

The Second Avenue Subway Project is a major capital expansion project of the New York City subway that will provide a dedicated line for the east side of Manhattan with a link to the existing subway network. The proposed alignment runs from Harlem in the north to the financial district in the south with possible extension to Brooklyn. The project is approximately 13.7 km long including 16 stations, and its estimated cost is about $17 billion. Under the current design of the whole subway route, 10 stations will be cut-and-cover and 6 mined caverns which will be constructed through vertical shafts within the right-of-way of Second Avenue. In addition, there are numerous multi-track tunnels, crossovers and connections that will be constructed in caverns. The excavated diameter of the bored tunnels is 6.6 m and the caverns span ranges from 12.0 m to 21.0 m. All caverns have rock cover less than their span. As the geology of Manhattan varies along its length, the subway will pass through both hard rock and soft ground and there will be multiple rock/soil interfaces along the alignment. The final engineering of the project was undertaken for the New York City Transit Authority by an AECOM led joint venture and the construction of the 86th St. Station, which is the focus of this paper, is currently underway by a joint venture of Skanska, and Traylor Bros.