The TBM cutterhead for Poland’s high-speed railway has been lowered into the launch chamber in Retkinia.
The 430-tonne cutterhead is part of the 4,000-tonne TBM that will excavate the tunnel beneath Łódź. TBM assembly began in July, in preparation for excavation of the 4.6km tunnel commencing in spring next year.
An overhead travelling crane with a lifting capacity of 450 tonnes was installed at the construction site to carry out the operation, which had a permitted tolerance of just ±5 mm.
Components already installed underground include gantries 2, 3 and 4, a substantial part of the machine’s shield, the erector substructure and the main drive.
The 130m-long variable density Herrenknecht TBM was previously used to construct the Hampton Roads Bridge-Tunnel in Virginia. Following completion of that project, it was transported to Germany and subsequently to Poland.
Porr is delivering the tunnel from Retkinia to Łódź Fabryczna station which is part of the high-speed railway line connecting Łódź with Warsaw and the new airport, and subsequently with Wrocław and Poznań.
The tunnel will have a diameter of around 14m and accommodate two tracks, allowing trains to operate in both directions.
Five intermediate access chambers are also being constructed along the route to serve as emergency evacuation facilities. The main tunnel construction works are scheduled for completion in 2029, followed by infrastructure testing and certification.
The excavated material will be conveyed by pipeline to a spoil separation plant. This is estimated to avoid approximately 80,000 lorry trips.
Porr is currently carrying out geotechnical investigations and structural assessments of buildings along the alignment. The tunnel will run partly beneath the historic Łódź Cultural Centre and a TBM reception chamber and a track junction chamber will also be built nearby.
Approximately 1,400 micropiles and jet-grouting columns have been installed beneath and around the building to strengthen the ground and foundations. The main geotechnical works have been completed and are currently undergoing acceptance procedures.
