St Petersburg giant TBM order confirmed

The world record TBM diameter is set to be broken again as the concessionaire for the planned Orlovski road tunnel (Nevskaya Concession Co - NCC) under the River Neva in St Petersburg, Russia, has ordered a 19.25m-diameter Herrenknecht Mixshield (see T&TI World News In Depth Mar 2011 p14).

On signing the order in St Petersburg, Russian Prime Minister Vladimir Putin took the opportunity to familiarise himself with the major highway project, the key place of the giant Herrenknecht Mixshield within it, and the operation of such a TBM.

The PPP-project under Russian government decree is planned to provide a 24-h crossing for traffic in St Petersburg (known as The Venice of the North) under the River Neva between the city centre and the northern districts and the orbital motorway. This will also allow a continuous passage for ships passing through from the Baltic/Volga Waterway, whereas previously a series of lifting bridges had interrupted free passage during the shipping season. The Orlovski Tunnel will allow longer bridge opening times for the ships

The tunnel bore will be over one kilometre long through mainly soft fluvial deposits under high groundwater pressure. It will carry two, three-lane carriageways on two levels, substantially increasing overall cross-river traffic capacity.

Including the trailing back-up equipment the Mixshield will be 82m long. The TBM itself will weigh 3800t and deliver 8400-kW of drive power to the cutterhead, allowing excavation of 600m3 of spoil per hour. Herrenknecht has previously said that the Schwanau factory was ready to begin manufacture as soon as the order was received. Tunnelling is scheduled to begin in the Spring of 2013 for operation in 2016.

The NCC concessionaire is in joint venture with the City of St Petersburg as client.

Herrenknecht’s previous largest TBM was made only last year for the Sparvo highway tunnel in Italy. This is a 15.55m-diameter EPB shield machine. The latest order is Herrenknecht’s biggest single ever, and comes after a long period of intensive preparatory engineering collaboration between the client and contractor. The increase in diameter gives a sectional area 50 per cent greater than the Sparvo Tunnel.

Other companies understood to be involved in the Orlovski Tunnel project so far include Danish consulting engineers COWI, the JSC Institute ‘Stroyproekt’ of St Petersburg, PSP Consulting Engineers, Poyry, Mott MacDonald, Freshfields Brukhaus Deringer and the Russian Research & Design Institute of Regional Development & Transportation.