Beginning of works – May 2014.
Completion of works – July 2021.
Total tunnel length – 6,682.05 m.
Scope of work
- excavation of a new single-track tunnel parallel to the existing tunnel using Lovat RM394DS tunnel boring machine with a cutting diameter of 10.2 meters, installation of the prefabricated reinforced concrete lining;
- laying of a ballastless continuous welded rail track on small-sized frames with installation of damper mats;
- construction of the western drainage adit – 1,500 m;
- construction of the eastern drainage adit – 1,747.36 m;
- construction of drainage adits No.1 and No.2 near the shaft, each 232 meters long;
- concreting of permanent walls and roof lining of the eastern and western drainage adits;
- ventilation shaft construction;
- construction of cast-in-place reinforced concrete tunnel portals.
The tunnel was driven from the western portal by the shield tunneling method. Adits, launching and exit chambers were excavated by the drilling and blasting method using Sandvik DC 120, Axera Т11-215 drilling rigs.