Breakthrough Bikoš Tunnel, Slovakia

​Project overview

The Rýchlostná cesta R4 is an expressway under construction in eastern Slovakia that will replace several sections of state roads. Larger cities along the expressway are Prešov and Košice. The construction of this dual carriageway R4 was carried out in 2 stages (currently under construction is a 4.3 km long 1st stage north of Presov with the Bikos tunnel, and a 10.2 km long 2nd stage with the Okruhliak tunnel). The R4 is part of the so-called Via Carpatia route. The client, the Slovakian motorway company NDS, will put the first stage into operation in 2023, while the tender for the second stage is scheduled for the coming year 2022.

Tucon bid for the project in 2019 and was awarded the contract.Tucon will carry out the excavation and the inner lining of the two tunnel tubes, including 3 cross passages between the east and west tubes, two widening areas (breakdown bays) in the middle of each tunnel as well as the 4 portal structures. The bridges will be built by the consortium partner. 

The 4 portal areas had to be constructed under the protection of pipe umbrella, the excavation in the clay and sandstone was mostly carried out by blasting, partly by excavator. Depending on the excavation classes, the excavation cross-section of the main pipes amounts to approx. 80-90m2, of the widening areas 133m2. The excavation was carried out in NATM, partly divided into calotte, bench and invert. The tunnel sealing is being constructed by Renesco AG.


On 27 May 2021, the project successfully celebrated the breakthrough of the first tube in the presence of high Slovakian political representatives. The inner lining work has started 2 weeks ago. At the moment 5 blocks have already been concreted. This work should also be completed by the end of this year.

Marti Tunnel AG
Seedorffeldstrasse 21
CH-3302 Moosseedorf
+41 31 388 75 10