Further Progress on HS2 Chiltern Tunnel
Work continues on the HS2 C1 project in the UK while the production of the TBMs progresses. According to a recent article published by ‘New Civil Engineer’, the construction of the 17m high headwall and ground reinforcement of the future south portal of the 16km long Chiltern tunnel has been completed by the Align JV.
The excavation of more than 160,000m3 of material took seven months, where the two TBMs will launch early next year. The ground behind the headwall is reinforced by soil nails that were driven into the ground to stabilise the ground and the shotcrete facing. A Steel pipe canopy was installed to pre-support the ground above the tunnels’ roof to limit ground movements and to allow the TBM to be operated at appropriate pressure levels from the launch.
Gall Zeidler Consultants have been involved as part of the Align Team in the design and construction of these tunnel-pre-support measures.