State-of-the-Art Application of Conventional Tunneling for the Northern Boulevard Crossing – East Side Access to Grand Central Terminal, New York
The East Side Access project in New York City, which will provide a new connection for the Long Island Rail Road into Grand Central Terminal, recently completed the crossing under Northern Boulevard. Tunneling involved the development of a very large cross-section at a springline diameter of about 18.4 meters in soft, water-saturated soils using SEM tunneling techniques (a first for New York) under very shallow cover. To enable tunneling beneath an existing subway tunnel, the above lying road way, Northern Boulevard, and an elevated rail viaduct without any disruption to the 24/7 operation of these major traffic arteries, the Northern Boulevard Crossing tunneling used ground freezing for pre-support and ground water cut-off, compensation grouting, vacuum dewatering and partial underpinning. This paper provides a comprehensive case history for this state-of-the-art urban tunneling project.