By rosebell
The single-shield machines will be used by the Schiavone Dragados Lane JV (SDLJV) to excavate the first 1.55km of the twin tunnels through the Palisades from North Bergen to the Hudson County Access Shaft in Weehawken.
Most of the gantries for the first machine have now been positioned in the launch shaft, according to the latest construction update from project owner Gateway Development Commission (GDC).
7f89cf8c 7728 9dc9 ebd2 ade9d24a8fa6Manufacturing and factory testing of the two Herrenknecht TBMs was completed last year, with the first machine shipped to the US in January and the second arriving in May. The machines have cutterheads approximately 8.7m in diameter and will construct tunnels with an internal diameter of around 7.7m.
GDC says tunnelling remains scheduled to begin during 2026.
SDLJV – comprising Schiavone Construction, Dragados USA and Webuild subsidiary Lane Construction – was awarded the US$465.6M Palisades Tunnel contract in 2024.
The package comprises approximately 5,100ft (1.55km) of twin bored tunnels through the Palisades rock formation, together with six cross passages and the Hudson County Access Shaft, where the two machines will be recovered following completion of their drives.
Preparations are also progressing for the considerably longer TBM drives beneath the Hudson River itself.
In April, GDC awarded the US$1.29bn Hudson River Tunnel Section contract to Traylor/Walsh/Skanska JV. The package comprises two approximately 7,250ft (2.21km) drives between the Hudson County Access Shaft in Weehawken and the 12th Avenue Access Shaft in Manhattan.
Two new TBMs will be used for these drives, designed to negotiate rock, soft ground and the artificially strengthened ground created by the Hudson River Ground Stabilization (HRGS) programme. The package also includes nine cross passages.
Early works by Traylor/Walsh/Skanska are now under way, including pre-construction surveys and test pits to establish the precise locations of underground utilities.
Ahead of the river drives, GDC has expanded the scope of its HRGS contract with Weeks Marine to remove approximately 500 timber piles buried in the Hudson riverbed that could obstruct the TBMs.
An area of riverbed approximately 1,000ft (305m) long and more than 100ft (30m) wide has already been stabilised. The ground treatment is intended to create more uniform and controllable conditions for the machines as they negotiate the soft river sediments.
Work is also advancing at the Hudson County Access Shaft in Weehawken, where the cap beam was completed in July. A 12ft-high (3.7m) floodwall has subsequently been constructed around the shaft perimeter to prevent stormwater entering during excavation.
On the New York side, Frontier-Kemper-Tutor Perini JV is delivering the Manhattan Tunnel Project, which extends between the Manhattan bulkhead in the Hudson River and the previously constructed Hudson Yards Concrete Casing.
The cap beam for the 12th Avenue Access Shaft has been completed and construction of its floodwall is under way.
In Hudson River Park, more than 400 underground pipes have also been installed for ground freezing. Cold brine will be circulated through the network to temporarily freeze and strengthen loose ground ahead of tunnel excavation.
Further east, construction continues on Section 3 of the Hudson Yards Concrete Casing. Two continuous 18-hour concrete pours in July placed more than 5,500yd³ (4,200m³) of concrete to form part of the tunnel box roof. The walls are now largely complete and the roof approximately halfway finished.
Early construction has meanwhile started on the US$711.7M New Jersey Surface Alignment contract awarded in June to Skanska Creamer Sanzari NJSA JV.
The package will construct approximately 7,540ft (2.3km) of infrastructure between County Road in Secaucus and the tunnel portal at Tonnelle Avenue, providing the future connection between the new Hudson tunnel and the existing Northeast Corridor.
Work includes 4,170ft (1.27km) of retaining walls and lightweight-fill embankment, 3,150ft (960m) of viaduct across the New Jersey Meadowlands and bridges over Secaucus Road and the Conrail and New York, Susquehanna & Western freight lines.
The contractor has now mobilised west of Tonnelle Avenue and established a work site for construction of the eastern abutment of the new bridge over the freight railway.
The Hudson Tunnel Project will ultimately provide two new rail tubes between New Jersey and Manhattan before the existing 1910 North River Tunnel is taken out of service in stages for rehabilitation.
The existing tunnel, which carries Amtrak and NJ Transit services on the Northeast Corridor, was inundated with saltwater during Superstorm Sandy in 2012.
The Hudson Tunnel Project forms the centrepiece of the wider Gateway Program to improve capacity and resilience on the Northeast Corridor between New Jersey and New York.
