(CONSTRUCTION 2009 - ІХ.2012)
The first stage of the Sofia Metro Extension Project, included in OP "Transport" includes the route: "Nadezhda Overpass - Central Railway Station - Sv. Nedelya Sq. - NDK - Cherni Vrah blvd." 6.4 km long with 7 stations.
The financing of this stage is carried out under Priority Axis 3 "Improvement of intermodality in passengers and freight transportation" of OP "Transport" by the ERDF. The grant by the ERDF amounts to 157 million Euros, with co-financing by the Sofia Municipality of 25% of the value of the stage. Application Form for funding together with the Cost-Benefit Analysis was approved by the European Commission in 2009. The final completion of the stage, after its adoption by the State Acceptance Commission at the end of August 2012, has took place in October 2012, as this stage was completed both physically and financially.
Fig. 1. Location of the routes of the Stages from the Sofia Metro Extension Project in the urban planning
Construction of this section has began in the spring of 2009 and has ended on 31.VІІІ.2012. It included construction of structures of tunnels and metro stations, architectural design of the stations, reconstruction and restoration of the affected urban infrastructure engineering, supply and installation of equipment of the management and operation systems of the metro, including 3 systems for transport automation and safety, 3 dispatch control systems, communication systems, sanitary-technical systems, etc. - i.e. complete engineering.
There were applied complex design and technological solutions, some of which are unique, due to the complex geological and hydrogeological conditions along the route and the passage under existing facilities, including under existing tunnels of Line 1, under subways, under Lion's Bridge, due to the requirement not to completely stop the traffic around the construction sites, as well as to preserve the archaeological finds in the center of the city.
Tunnels in the section "Nadezhda Overpass - Patriarh Evtimiy blvd." with a length of 3.8 km and 4 stations are double-track tunnels with an inner diameter of 8.43 m, completed by aspecially produced for the conditions of the Sofia Metro tunnel boring machine (sealed hydro-shield) by the German company "Herrenknecht".
Fig. 2. Cross section of the double-track tunnel constructed by the means of shield method and general view of the TBM
Equipment is supplied by leading companies such as Siemens, Erricson, ThyssenKrupp and others. Metro stations are constructed according to individual architectural solutions, some of them are shown in Fig. 3 and Fig. 4.
Fig. 3. Figure 3а shows a view of the tunnel boring machine at its entrance in Lavov Most metro station. Figure 3б. shows a view of the already completed MS Lavov Most
Fig. 4. Figure 4а. shows a view from MS Serdika II, and on Fig. 4b. is shown the entrance concourse of NDK station.