The work was carried out under difficult hydrogeological conditions
“The tunneling of the left running tunnel of the connecting line between the Big Circle Line (BCL) and Zamoskvoretskoye electric depot is complete”, said Andrey Bochkarev, Deputy Mayor of Moscow on Urban Planning and Construction. Mosinzhproekt Engineering Holding is the operator of the Moscow Metro Development Program.
“The second tunnel connecting the Zamoskvoretskoye depot and the BCL has been completed. The connecting line is needed to deliver trains from the depot to the Big Circle Line, part of which will be the Kakhovskaya line undergoing reconstruction. At the end of last year, metro construction workers laid the right-hand adjacent tunnel. Placing concrete in the track superstructure is under way,” said Andrey Bochkarev.
For his part, Yuri Kravtsov, General Director of Mosinzhproekt JSC, explained that the work was carried out in difficult hydrogeological conditions: the soil is composed of loamy soils and water-bearing sand.
“The ‘Marina’ tunnel boring machine with a diameter of 6 m completed the tunneling of the 784.8-meter left running tunnel from the site, located near Zamoskvoretskoye electric depot up to the disassembling chamber between Kakhovskaya and Varshavskaya stations of the Big Circle Line,” said Yuri Kravtsov.
For his part, Sergei Zhukov, General Director of Mosmetrostroy JSC, contractor for constructing several sections and stations of the BCL, pointed out that additional safety measures have been applied during the tunneling under the existing transport facilities.
“We carefully conducted the tunneling shield under Varshavskoe Highway and next to the active section of the metro, the Varshavskaya station under reconstruction. Besides, additional management actions were required: during this section, we reduced the cruising speed of the TBM and monitored the pressure in the system,” said Sergei Zhukov.
During the course of work, the soil was discharged to the surface through the installed pipeline. This is the method used by TBM with hydraulic loading, designed to construct the running line in difficult geological conditions.
In the future, five points will be trailed in the tunnel to complete the integration of the connecting line between the metro and the Zamoskvoretskoe electric depot.
The Big Circle Line project is the largest in the history of the Moscow Metro construction. It is assumed to construct 31 stations, 12 of which have already been opened for passengers, 16 more are under construction, and three stations of the Kakhovskaya Line, which will be part of the BCL, are under reconstruction.