EXTENDING NEW YORK CITY’S NO. 7 LINE SUBWAY

摘要

The primary purpose of the No. 7 Line Extension Project is to promote transitorientedrnredevelopment of the Hudson Yards Area of New York City. The project willrnextend the existing No. 7 (Flushing) Line approximately 2.0 km (1.3 miles) to the westrnside of Manhattan. In December 2007, S3II Tunnel Constructors JV, a joint venture ofrnShea/Skanska/Schiavone was awarded a $1.15 billion contract by the MetropolitanrnTransportation Authority (MTA) to construct twin bored tunnels, five cross passages,rnand the 34th Street Cavern Structure.rnThis paper will focus on the means and methods used to construct the two 6.86 mrn(22'-6") diameter tunnels. It will discuss the tunnel boring machine, hereafter referredrnto as TBM, selection process and support systems; precast segmental lining, requiredrnground freezing, and converging alignment.