The Tunnel Boring Machine finished its work in Sofia at Underground Station 6, constructed by Trace Group Hold

27 Feb 2019

The tunnels of the third underground line in Sofia are already dug. The Tunnel Boring Machine (TBM) finished its work today - February 27th, 2019, emerging on the surface at the 6th Underground Station (at “Theater behind the Channel”), which is being constructed by Trace Group Hold PLC.

Two years ago, the TBM specifically commissioned for Sofia third underground diameter, made its first dig at 14th Underground Station (Gotse Delchev Blvd. and Knyaz Boris Blvd. crossing). The machine passed nearly 7 km along the route of the new underground line and ended its work at 6th Underground Station, the junction of Evlogi Georgiev Blvd. and Yanko Sakazov Blvd. The event was attended by engineer Stoyan Bratoev, director of Metropolitеn Sofia, Mrs. Yordanka Fandakova, Mayor of the capital, Mr. Stanko Kantar - executive director of Belgrade metropolitan company, representatives of companies working on the underground construction, journalists and citizens.

The dismantling of the machine will take place within the next month, after which Trace teams will begin the construction of the railway from the 6th Underground Station (called "Theatre" Station) to the 8th Underground Station at “Orlov Most” Bridge.

The most complex part of the work of the TBM was the passage under both Perlova and Boyana River, as well as the drilling of the tunnel a meter and a half under the existing line 1 of the subway.

Currently, the first stage of construction of Sofia third underground diameter is ready at 88%. Mrs. Fandakova and Eng. Bratoev inspected the activities of Underground Station 6. The executive director of Trace Group Hold Eng. Boyan Delchev explained that the tunnel and the railway track have already been completed. He added that the architectural appearance of the station is currently being performed.

By October 2019, is expected to be completed the construction of the first five metro stations and the three others must be finished by the end of the year. The metro stations from Krasno Selo quarter to Underground Station 18 (in Ovcha Kupel quarter) will be put into operation in the midst of 2020. 14 of 30 trains that will serve the third line of the subway, have been already delivered, informed Prof. Bratoev.

The Serbian guests have visited the construction works at Underground Station 18 which is the only one being implemented under the New Austrian Method. "The whole central section of the third metro-diameter is dug through the shield tunnelling method that is suitable for long tunnels. At Underground Station 18, this method can not be used due to the specificity of the location and the tunnel length. That is why the New Austrian method is used there” specified engineer Vladislav Petrov, project manager at Trace Group Hold, adding that "Its huge advantage is that it does not affect the adjoining infrastructure in any way”. In this case, it goes under Sofia ring road and under the railroad - they both remain intact, as well as the local engineering infrastructure, preserving thus the people from considerable discomfort.

A covered pedestrian crossing under the railway line (Sofia-Pernik-Radomir) and the ring road of Sofia will be built for further facilitation of the citizens. It will connect the Ovcha Kupel quarter with Gorna Banya quarter, the future railway station and the metro station.

The Tunnel Boring Machine video is available here.