Engineers at Świna tunnel are starting the freezing process which will take 40 days. The ground will be frozen to minus 10 degrees Celsius for sand and clay, and minus 8 degrees Celsius for chalk. This is achieved by transferring the heat from ground to air with the help of compressors, condenser, evaporator and the freezing pipes with brine solution in them cooled to minus 35 Celsius.

Freezing makes the ground watertight, hence allows the tunnelling without water rush.

The Świna tunnel is 3,2 kilometer long single-tube tunnel with 3.5 meter wide lane in each direction and two two meters wide emergency lanes.

The tunnel is built by GÜLERMAK and PORR consortium. The total cost of the investment is over PLN 900 million, of which 85% comes from the European Union, the rest from the Świnoujście town budget.

https://swinoujscie.naszemiasto.pl/budowa-tunelu-w-swinoujsciu-coraz-blizej-konca-trwa-wielkie/ar/c3-8711691