On the 27/01/2020 the TBM Gaia (diameter 11 m) re-emerged at the Stevenshof district of the A44 in Leiden, after 6 months tunnelling and  2,250 m from its starting point at the A4 motorway. 225,000 m3 of soil has been excavated and 7,840 concrete tunnel segments were installed.

The receiving shaft was first submerged before the arrival of the TBM, in order to provide counter pressure against the groundwater outside the construction pit. The TBM has arrived under water in the receiving shaft, the space between the tunnel wall and the wall of the construction pit has to be made watertight and the water will then be lowered step by step.

The TBM will be dismantled in the coming weeks and transported back to the starting shaft at the A4 where it will be reassembled to start again on the second tunnel, the contractor Comol5 will start drilling in April 2020.

For further information please click here and nl/41 for tunnelbuilder archive and also visit https://rijnlandroute.nl  and https://www.comol5.nl/. 06/20.