ABSTRACT
In 2015, the Tunnel Boring Machine (TBM) used for the First Street Tunnel Project (FST) was abandoned in place after completion of the 822 m long (2700 ft) tunnel drive. Later in 2022, as part of the Northeast Boundary Tunnel (NEBT) project, the connection between FST and NEBT was completed, including a challenging removal of the FST TBM from inside the NEBT. This paper describes the design and construction efforts necessary to perform the final connection at the intersection of FST and NEBT, including ground improvement, SEM excavation works, TBM dismantling and installation of permanent lining.
