First breakthrough celebrated on Bikos Tunnel

The R4 dual carriageway will link cities such as Prešov and Košice and will replace some sections of existing state roads. Construction is being undertaken in two stages: the 4.3km-long first stage north of Prešov which includes the Bikos Tunnel; and the 10.2km-long second stage which features the Okruhliak Tunnel.

Awarded the contract in 2019, Tucon is excavating the two Bikos tubes and installing the inner lining, as well as constructing three cross passages, four portal structures, plus two widened areas at tunnel mid-points for vehicle breakdowns. The main tubes have a typical excavation cross-section of around 80-90m2 which increases to 133m2 at the widened areas.

Excavation has been undertaken using NATM, partly divided into calotte, bench and invert. Both drill and blast, and excavators have been used to mine through the variable sandstone and clay geology. Pipe umbrella was used for the four portal structures.

Work to install the inner lining began in late May, and with five blocks already completed, this aspect of the work is expected to be finished by the end of 2021. Sheet membrane waterproofing will be installed by Renesco.

The first stage of the R4 is expected to be operational in 2023, while the tender for the second stage is scheduled for 2022. Ultimately, it will form part of Europe’s north-south Via Carpatia route that will link Klaipeda, Lithuania with Thessaloniki, Greece, and with off-shoots into Romania and Bulgaria.