Construction of Teatralnaya subway station in St. Petersburg
This station was supposed to be built in 2014‒2018, but the deadlines have been shifted. There have been three tenders for construction of this station. The first one, in 2014, failed because of lack of interest. Metrostroy won the second in April of 2015 and started to relocate utilities.
But the customer ultimately declared this tender invalid. The station’s opening was postponed to 2020. In August of 2015 Metrostroy won the next tender and signed the contract to build a section of the Pravoberezhnaya line from Spasskaya to Bolshoy Prospekt. Teatralnaya station is an intermediate station on the line, and its underground hallway will be erected under this contract.
What makes the project stand out
Teatralnaya station may be one of the most challenging objects Metrostroy has ever built in the center of St. Petersburg. The builders will have to pass under the new and the old buildings of Mariinsky Theater. After the hallway is completed, Teatralnaya station ramp tunnel will be started. No covered pavilion is planned on the surface: passengers can come out to the theater from an underpass.
Metrostroy states that the theater’s foundations and surrounding buildings are safe: the tunnel’s roof will be 46 m deep. The famous foundation of the new theater building, created with so much effort also by Metrostroy, is at 13 m depth.
Metrogiprotrans from Moscow is monitoring the effects on the nearby buildings, but it is not yet certain that they will not sink because of the subway.
When will Teatralnaya station open?
The official date for the construction end of Teatralnaya station hallway is late in 2019. The city administration planned to make a surface exit a little later, trains were to pass the station without stopping.
But the plans have changed. According to the City Infrastructure Development Committee, the ramp tunnel and square exit project documentation should be approved in the first quarter of 2017. Efforts will be made to finish them in time for the hallway, but the administration reserves the right to change the time table for the second stage.
Work progress at Teatralnaya station
No construction was done in 2014‒2016. Archeologists searched the site for artifacts on behest of the Ministry of Culture.
Test drilling and analysis of the soil were performed. The results were sent to the Ministry of Culture. Building teams started working only in the last week of April.
Getting to the underground part of the work requires arranging an envelope contour (walls) to the future shaft through which machinery and workers could pass. The shaft will be 32 m deep and 6 m broad.
The contour will be arranged by drilling holes, reinforcing concrete elements in them and fixing them in place with concrete. With this method 25 out of 32 piles have been fixed, 7 remain. After soil extraction and reinforcing the wall the shaft will be ready.
But the builders are meeting with the first obstacles: a boulder zone was discovered at the depth of 21‒26 m. Two piles came up against boulders and remained at the 24.5 m depth. A decision was made not to extract the piles but fix them in place with concrete and retain as a part of envelope.
Next on the agenda
The next stage is shaft working. The first 15 m will be open-cut. At the same time the entry structural part and rough reinforced-concrete coating for the shaft will be completed. At this stage all underground linings are rough. Closer to commissioning they will be finalized.
After this, there will be a short technical pause to set up the tunneling complex: lifting gear and drop hammer will start their work. Then again tunneling, but open-cut and under soller. Actual tunneling (29 m) up to mine-shaft inset in front of underground infrastructure. This will be followed by working horizontal shafts under the old and the new buildings of Mariinsky Theater.
The size of the construction site for Teatralnaya is unusually small.
Metrostroy’s site right now takes up a tiny space between Soyuza Pechatnikov Steet and Glinka Street, next to the theater’s building.
After the shaft is completed and tunneling towards Dekabristov Street begins, the site will be expanded, which may create logistics problems. Up to 400K cb m of soil will have to be taken off site daily, and dumpers can only be half filled according to new maximum weight regulations for truck transport. One truck will be able to take no more than 10 cb m of soil.
In case of serious jams a special area to temporarily store up to 300 cb m of soil will be provided next to the theater.
During the second stage ‒working of ramp tunnel and surface exit, logistics will become even worse. Vehicle traffic on Teatralnaya Square will probably have to be blocked entirely.
The only way to success is through stable and well-organized daily supplies.