CERN: Mining tunnel for technical equipment of the HL-LHC

Meyrin, Switzerland

The Large Hadron Collider (LHC) at CERN is the world’s largest particle accelerator. In order to increase its potential for future experiments during the next decade still further, the LHC is currently undergoing an upgrading. Doka supplied the crown-arch formwork for four 50 – 70 metre-long crossways, for which three formwork carriages and a large amount of customised formwork were used.


  • Considerable time pressure to complete the work before the planned restart of the accelerator in eraly 2021
  • High complexity of various structures
  • Need to ensure that formwork elements could be reused
  • Elaborate construction workflow


Using bolt-on wheel sets form a Doka supporting construction frame. With these, the four elements can be manoeuvred accurately inside the tunnel. The bolt-on wheel sets are then removed in the tunnel, and the formwork carriage is set back on its heavy-duty rollers.

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Project data

Construction period:
2018 - 2022
Marti Tunnel AG

Building data

LHC circumference:
26,659 m
Tunnel diameter
approx. 3.80 m
average depth of tunnel below the earth´s surface:
100 m (min. 50 m, max. 175 m
Operating temperature:
1.9 K (-271,3 °C)
Electricity consumption:
approx. 120 MW
Annual data volume:
50,000,000 GB (=50 PB)
Total construction costs:
approx. CHF 6.5 billion

Systems used


Services used

Formwork Planning