The technology of construction of single-wall stations of the St. Petersburg Metro provides for the development of the station core, which contains the bulk of the rock excavated during the construction of the station, after the construction of the upper vault. Until recently, this work was carried out mainly with the help of jackhammers.
When conducting the stations of the Leningrad Metro, the tunnels are conducted first, then the calotte slot (the upper part of the station vault with a height of 3.5 m), and the main part of the station is developed with the help of excavators of the "Gidravlik" type and boom tunneling machines.
