Cut-and-cover tunnels

In the 1970s and 1980s, Wenceslas Square became one of the symbols of the construction of the metro, as it was gradually transformed into a massive construction pit in which stations of all three lines - C, A and B, including transfer routes, were gradually built.

Track tunnels were also built on a smaller scale using the technology. The construction consisted of closed reinforced concrete monolithic frames with insulation. Thus, sections of two-track or two single-track tunnels were built, which were usually connected to the excavated sections. The monolithic concrete allowed a transition between the two types. An example is the section behind Pankrác station in the direction of Budějovická. In places where groundwater was present, they were dug under the protection of underground walls. The underground walls formed the side walls of the structure. In the transition from a two-track tunnel to two single-track tunnels, the underground walls also formed the central dividing supports. This method was used in the construction of the line sections between the stations Hlavní nádraží and Muzeum and beyond Muzeum up to the tunnels excavated under Mezibranská street.

Cut-and-cover tunnelling is one of the less economically demanding technologies. However, it is only applicable where tunnels or stations are located at shallow depths. In some cases, cut-and-cover tunnels require sacrificing surface structures that need to be demolished. In addition to the impact on urban development, other disadvantages of building cut-and-cover tunnels in the city centre became apparent during the construction. Citizens soon felt the effects of the large-scale construction activity, with noise, dust, and aggravation of the already congested traffic situation. In addition, the first and second underground levels of the city turned out to be densely occupied by technical infrastructure. The combination of all the influences made cut-and-cover tunnelling in the city centre seem less suitable, and the logical choice was routing subsequent metro lines to greater depths underground.

The first operational section of Line C is characterized by the search for the optimal design of the excavation stations, which are therefore different in layout. Florenc station is a shallow, mainly two-storey station with a three-storey section in the southern block for technological equipment and turnaround tracks. I.P. Pavlova is considerably deeper than the other stations on the first section of Line C and was originally intended to be a three-vault station. In the end, it was designed as a six-storey station with built-in garages above the platform.

Pražského povstání and Budějovická stations are covered with prestressed prefabricated beams and the platform area is thus not disturbed by the columns. Pankrác station is the only one with escalators situated in the middle and, experience from its operation shows that this solution is less suitable because the massive escalator bodies disturb the integrity and clarity of the platform.

The great economic and implementation advantages of underground construction were evident in the outskirts of the city, where the construction of the underground was ahead of the surface development. An example is the second operational section of line C (Kačerov - Háje), which serves the residential part of the southern part of the city, or the fifth operational section of Line B (Nové Butovice - Zličín) in the south-western part of the city.   

Two excavated stations are unique in their construction within the Prague metro. These are Rajská zahrada and Střížkov stations. It is mentioned earlier that the tunnel construction would be filled in. Why not use the excavated construction pit and cover it with an airy steel structure with many transparent elements so that the station is accessible to daylight for most of the day? If the architect is given the opportunity, truly unique and imaginative designs can be created. Rajská zahrada and Střížkov stations are just such structures. Both received awards; Rajská zahrada the Building of the Year award in 1999 and Střížkov the European Steel Construction Association award in 2009.