In 2009 Geotechmin OOD signed a contract with Metropolitan PLC for “Design and construction of Metrostation 11-II with the tunnel section after it and the adjoining underground parking lot above the two facilities”.

The construction works on Metrostation 11-II, which is part of the second diameter of Sofia Metro, commence in 2010. The subway station is situated under Cherni Vrah Blvd near Kempinski Hotel Zografski, and is going to be the deepest metro station in Sofia.

This is one of the most difficult underground sites that have ever been built in Sofia. The metro station will be constructed at a depth of 25 to 32 m under a boulevard with extremely heavy traffic. To ensure the convenience of Sofia citizens Geotechmin and Metropolitan have chosen such construction methods that will avoid closing of Cherni Vrah Blvd during the construction works.

The project will be executed using various technological methods. The excavation works to the level of bottom slab will be carried out through the Milan Method. Stability of the diaphragm walls will be ensured by anchoring. The construction will be carried out using the “bottom-to-top” method. The site is designed to resist an earthquake measuring 9.0 on the Richter scale.

The length of Metrostation 11-II together with the tunnel section is 207 m, and its width is 18 m. The metrostation is situated entirely under the ground and will be built in several levels. The station and the tunnel will be situated at the lowest level, and above them a parking lot and a shopping area will be constructed.