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High Speed 2 Rail, Contract C1 Project

High Speed Two (HS2) Limited

HS2 is a new high-speed rail line that will be the backbone of the UK’s rail network. Phase One of this project will connect London to Birmingham by between 2029-2033. In July 2017 the Align joint venture was awarded the C1 package of HS2. Align is a joint venture of three international infrastructure companies; Bouygues Travaux Publics, Sir Robert McAlpine, and VolkerFitzpatrick. C1 consists of 21.6km (13.5mi) of high-speed rail infrastructure that includes a 3.5km (2.2mi) viaduct, 16km (10mi) twin-bored tunnel and five vent shafts accommodating both intervention and tunnel ventilation facilities.

Design Team Services:

Gall Zeidler Consultants (GZ) as part of the Align Team, provided the design for all cross passages, the ground treatment design and are serving as a geotechnical specialist. GZ’s scope also includes the development of the Geotechnical Baseline Report, the Durability Report and Tunnel Obstructions Assessment as well as the Settlement and Potential Damage Assessment.



Chilterns, United Kingdom


2017 – Present


The Chiltern Tunnel comprises twin bored tunnels five ventilation and intervention shafts and 38 SCL / SEM Cross Passages


16km (10mi) twin-bored tunnels with Cross Passages spaced every 500m (1,640ft)


TBM Tunnel I.D. 9.1m (30ft) / Cross Passage I.D. 3.5m (11.5ft)


Tunnel and Cross Passages excavation will primarily be through the Cretaceous White and Grey Chalk Subgroups that constitute the Chiltern Hills. The Chalk shows varying degrees of weathering with numerous dissolution features and fracturing along fault lines. The groundwater level is maximum 30m above the tunnels' roof.


US $2 Billion (£1.6 Billion)




High Speed Two (HS2) Limited