Tunnelling recently got underway on the US$231m Swinoujscie Tunnel under the Swina Strait between the islands of Uznam and Wola in the northwest extremity of Poland.

Work has been ongoing on the project since September 2018. Porr and Gulermak Consortium are building the 1.78km-long tunnel of which 1.48km is being excavated by TBM as part of a 3.2km investment that includes two huge launch and receiving shafts and two ramps built by open-trench and cut-and-cover.

The giant 13.46m-diameter slurry TBM from China Railway Engineering Equipment Company (CREG) and an 18-strong crew began mining from a 120m long by 20m-wide launch shaft.

Manufacture of the precast concrete segmental lining rings has been ongoing over the past few months at a plant located 400m from the launch shaft. This ensured around 1,600 segments (200 rings) were available before the start of construction.

When completed, the 12m internal diameter, single tube, bi-directional tunnel will comprise two road lanes, each 3.5m wide plus 2m-wide emergency lanes. At its deepest point, the tunnel will be 38m below sea level and will provide a direct link between Uznam and the Polish mainland.

Working around the clock, the TBM is expected to complete its bore in September 2021 by which time it will have mined around 210,000m3 of soil. Italy-based SWS is providing executive design, on-site supervision and final design of the tunnel. The project, of which US$196m has been provided by the European Union, is anticipated for completion in the last quarter of 2022.

For the original article, please visit TBM excavation begins on Swina tunnel - Tunnels & Tunnelling International (tunnelsonline.info).