St Petersburg Neva River highway revival 07 Mar 2019

The Russian Federal Government, together with the authorities of the St Petersburg region, plans to resume building of the Orlovsky highway project but this time as parallel 10.3m diameter tunnels of about 2,200m long to accommodate two traffic lanes in each direction at a depth of 9m beneath the bed of the Neva River, rather than as the single-tube double-deck tunnel of three lanes on each deck developed back in 2007 using a record-breaking 19m diameter TBM proposed and procured in its design by Herrenknecht of Germany.

Fig 1. Technical concept of Orlovsky tunnel, which was created in 2008

The new project, being developed by Moscow design and engineering company Metrogiprotrans, is revived after a pause of almost eight years, and will be located under the historic area of St Petersburg, under Piskarevsky Prospect and Orlovskaya Street to provide the much-needed link under the Neva (Fig1). Renamed the Sredneokhtinsky project, it is expected that the tunnel will be carried out by the Moscow-based company OJSC Metrostroy, a main contractor for the building of the Moscow and St Petersburg metros, and be completed during the next three and a half years.

The new tunnel is considered as a cheaper and revised alternative to the Orlovsky Tunnel initiative, which was proposed during the investment boom in St Petersburg and for which a technical concept was officially adopted and the design of the huge 19m diameter TBM commissioned with Herrenknecht.

At that time, the project was being implemented by the Neva Concession Company (NCC), which signed an investment agreement in 2010 with the authorities of St Petersburg, headed by Valentina Matvienko. A year later, the cost of the project exceeded RUB 80 billion (about US$1.23 billion) - two times higher than initially estimated at RUB 40 billion. It was a change of power in St Petersburg, and the appointment of Georgy Poltavchenko as a new Governor of the city, that resulted in the suspension of the project, as he found its implementation too expensive for the city’s budget and decided to put it on hold.

Arrival of Vladimir Beglov as the new St Petersburg Governor creates conditions for resuming the project, in accordance with its revised design and at a revised total cost not to exceed RUB 39.9 billion (about US$606 million).

Vladimir Beglov, a new St Petersburg governor, who became a main initiator for building of Sredneokhtinsky tunnel

Where the initial concept involved a single-tube double-deck tunnel of up to 19m o.d. to accommodate six lanes, the revised version will comprise twin tubes for four lanes and be excavated using the 10.5m diameter Herrenknecht Nadezhda shield purchased by Metrostroy for €22 million from Herrenknecht AG in December 2015 for excavation of two sections of the St Petersburg Metro. According to an official spokesman of Metrostroy, the machine has already proven itself and can be used for the construction of the twin-tube four-lane Sredneokhtinsky highway tunnel.

According to an official spokesman of Metrogiprotrans, one of the leading infrastructure planning companies in Russia, which also participates in the project, the speed of excavating the tunnel with the Nadezhda TBM will be about 300m/month.

Currently the authorities of St Petersburg are considering ways of funding the project with one possibility including a PPP public-private partnership concept. Part of the funding could be provided also in the form of infrastructure bonds. The toll tunnel, with a fee of RUB300 (US$4.50), will have a traffic capacity of up to 60,000 cars/day.

Experts of OJSC Metrostroy and a spokesman of the authorities of the St Petersburg believe there is no real alternative to the tunnel in the current conditions. A spokesman of Metrostroy said: “Another option may be a high-level bridge, but this will lead to the need of building of technically complex entrances and junctions, which will result in a significant increase of the costs of the entire project.” A bridge would also have a negative effect on the world-renowned urban views of historic St Petersburg.

Nadezhda shield during building of Novokrestosvky station of the St Petersburg metro

Most experts however warn of some potential risks during actual building of the tunnel. Valery Kuznetsov, Director of the mechanization department of Metrostroy, said: “Implementation of the project will be associated with serious technical difficulties, taking into account complex ground in the bend of the Neva River and most importantly, construction of large portal structures to ensure convenient entry and exit out of the tunnel.”

The same position is shared by Johannis Henning, CEO of Herrenknecht Tunnelservis, a subsidiary of Herrenknecht, who has worked on several applications of large diameter Herrenknecht TBMs in the Russian capital Moscow including the Lefortovo highway project in the early 2000s. Henning said one of the biggest challenges during the conduction of tunnel works in St Petersburg is the abundance of boulders in the saturated soils and the variability of ground conditions. According to Henning, boulders not only prevent normal operating of the shield, but also damage its working body. He added that the situation is aggravated by the fact that technicians and service workers cannot always determine whether repairs are required, and any such inspections and repairs require hyperbaric interventions.

Implementation of the project has been welcomed by some leading Russian scientists in the field of civil construction and tunneling works. Oleg Bely, Chairman of the Council of the Russian Academy of Sciences commented: “The construction of the tunnel under the Neva will certainly improve the transport infrastructure of the city. We have underestimated the possibility of using underground space in the past, paying the biggest attention for the building of subways.”