As three new stations open on the St Petersburg Metro, the Russian Federal Government and the authorities of St Petersburg plan to further accelerate the expansion of the metro this year, according to recent statements made by representatives of the local authorities and industry analysts.
Construction of the Frunze radius line – one of the sections of the Frunze-Primorsky Line 5 of the St Petersburg Metro – was completed at the beginning of October 2019, including the three stations Prospect of Glory, Danube, and Shushary (Fig 1). Capacity on this line is 40 trains per hour in each direction with 997,000 passengers expected to use the three new stations per day. The cost of the extension was RUB34 billion (about US$523 million) and will help connect the historical city centre to its north-western and southern districts. Implementation of the project is personally overseen by the newly elected St Petersburg governor Alexander Beglov.
The overall expansion project will extend the St Petersburg Metro from 124km to 156km by 2027. In addition, the number of stations will increase from 72 to 85, with 80 of the stations underground. In addition, the number of metro depots will increase from five to seven. Part of these plans also includes the construction of new entrance halls and interchange stations. Total investment is estimated at more than RUB170 billion (US$2.5 billion).
Implementation of the metro project is expected to be carried out by Metrostroy, one of the largest engineering companies in Russia and the main contractor of St Petersburg Metro construction works. This is despite the fact that the local authorities have repeatedly announced their intention to end the monopoly of the company in the St Petersburg tunnelling industry in years to come.
According to statements made by an official spokesperson of the St Petersburg regional authorities, the local government is conducting talks with potential contractors that may participate in the project, including some well-known foreign construction and engineering companies. One of them is ICA Construction, a joint venture of IC Ictas Insaat of Turkey and Astaldi of Italy, which already has experience of some major infrastructure projects in St Petersburg, including a new terminal building at Pulkovo Airport and the central section of the major Western High-Speed Diameter city highway.
However, Dmitry Grafov, a well-known St Petersburg expert in the field of tunnel building, said the existing concerns of the St Petersburg Government regarding further participation of Metrostroy in the project are generally unfounded, as the company remains one of the most experienced tunelling contractors in Russia. “So far, they have built all stations of the St Petersburg Metro, 64 of them located underground,” he said.
In the meantime, Metrostroy hopes to continue its participation in the project despite the current uncertainty. The company plans to continue the use of technology that significantly speeds up construction of tunnelling works. For example, part of its plans include the use of single-tube double-track tunnels and systems that allow for the permanent rail track invert to be installed concurrent with excavation works.
This construction method became an innovative development of Metrostroy and received a patent protection from the Russian Federal Service for Intellectual Property (Rospatent). According to the company, construction of double-track tunnels and the parallel works method can almost double the speed of tunnelling works, although the method is only recommended for the sections of 5km or longer.
With regards to equipment, a specialised 10.72m diameter TBM was designed and supplied by Herrenknecht for the project, capable of excavating at a 30° decline for escalator shafts. One of its major advantages is its suitability for use in dense urban areas, which is especially important when taking into account the large historical centre of St Petersburg. According to experts at Metrostroy, conventional tunnelling works in St Petersburg can be only carried out at a depth of 40-60m where dry Cambrian clays are located. Most of the works in the upper layers are usually complicated by a high content of groundwater, which requires its constant retaining. Therefore, most of the metro stations of St Petersburg are located at a depth of more than 50m, although tunnels, especially those under river channels, are usually located at greater depths.
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