Underground tunnels B12/13 to B19, Warsaw
Client: Warsaw Metro
Technical data:
Total tunnel length – 4900 m
Enclosure diameter – 5.2 m
Technology:
Mining and construction methods with the use of a non-mechanized protective disc.
The Warsaw Underground is one of PeBeKa’s main transport construction projects. Apart from the two track tunnels drilled under Łazienkowska Street, PeBeKa built seven eastern track tunnels between “Politechnika” and “Marymont” stations. Additional infrastructure was also created: small shafts, ventilation centres, junction chambers.
Due to geological conditions this task was carried out with preemptive injection. The mastered and implemented modification of hitherto disc drilling method consists of chemical consolidation of loose sands. In the tunnel crown a screen is made from sand glued chemically together, that comes ahead of the advancing disc. This procedure effectively eliminates uncontrolled landslides of sand into the tunnel.
During the boring of tunnel B12/13 just before reaching the “Centrum” metro station, an obstacle was encountered, it was an active four-track two-way PKP railway line tunnel. This was one of the most serious technological and design problems in this part of the construction. Thus a technology different from the one proposed in the design was used, one using hydraulic dilators for crushing concrete.