What tools were used to build the Chunnel? How are the tools operated?

Question

The Chunnel is the channel tunnel that goes across the English Channel.

Answer 1

Digging the tunnel took 15,000 workers over seven years, with tunnelling operations conducted simultaneously from both ends. The prime contractor for the construction was the Anglo-French TransManche Link (TML), a consortium of ten construction companies and five banks of the two countries. Engineers used large tunnel boring machines (TBMs, mobile excavation factories that combined drilling, material removal, and the process of shoring up the soft and permeable tunnel walls with a concrete lining).

In all, eleven TBMs were used on the Channel Tunnel:

    * three French TBMs driving from Sangatte to under the Channel,

    * one French TBM driving the service tunnel from Sangatte cofferdam to the French portal,

    * one French TBM driving one running tunnel from Sangatte cofferdam to the French portal, then the other running tunnel from the French portal back to Sangatte cofferdam,

    * three British TBMs driving from Shakespeare Cliff to the British portal,

    * three British TBMs driving from Shakespeare Cliff to under the Channel.