Kanonersky Tunnel

Kanonersky Island is an Artificial island in Saint-Petersburg. it was build as consequence of building Sea Canal to further deepening of Neva Bay[9]. by expansion of industrial area of St. Petersburg, it become home to large shipbuilding enterprises. means for transporation were ferry and private boats and exploiting Icebreaker was mandatory during cold period of year[10] by using Big port Saint Petersburg.[11]. Thus connecting this industrial island to the mainland was suggested either by bridge or tunnel and building tunnel preferred.

For the construction of Kanonersky Tunnel, several scientific institutes were involved for design and feasibility studies such as Lengiprotrans,LENMORNIIPROEKT , SKB Glavmostostroy, Research Institute of Transport Construction, PGUPS,MIIT,Metrogiprotrans, Moscow State University of Environmental Engineering[12]. The tunnel project was prepared by Lengiprotrans[2] while the building work was carried out by Giprostroymost.[13] Geodetic maintenance of the building was assigned to the PGUPS.[14]

The Tunnel was built using a sunken tube or immersed tube method. The main part is consisting of five identical prefabricated reinforced concrete sections. Each length is 75 metres (246 ft), width 13.3 metres (44 ft), height 8.05 metres (26.4 ft), weight about 8,000 tonnes (8,800 short tons)[15]. The structure is made of monolithic reinforced concrete with a thickness of the tray, walls and floors of 0.93 m.of buried sections: The length of the site dipping sections totalled 375 metres (1,230 ft).

For the building of the sections on the bank of the Sea Canal, the original dock-sluice was constructed. After sluicing the created sections, the end faces were closed by metal partitions. They were counterbalanced by water and transported along the Sea Canal to the place of immersion. They were then joined to an earlier established section, forming a uniform design. For the control of the immersion, divers worked underwater.[13]

The full length of the tunnel was 927 metres (3,041 ft).[3] The tunnel has two lanes and a footpath. Along with cables for electrical supply and communication; water supply and central heating pipes connect Kanonersky Island with the city.[16]

Due to nature of Immersed tube method, constant monitoring and repairing has been exert, [3].the first Maintenance, repair and overhaul was carried out between the period of 1997 to 2002, and task included lighting, ventilation systems were replaced, three drainage pumps were installed[3]. In 2004, Lengiprotrans, one of the principal constructor, carried out a repair work.[2] In 2006, there was a mooring damaged over the tunnel, from it the tunnel was also damaged.[17] At the end of June 2009, tunnel repair was again required, after it was determined that the drainage systems needed a replacement.[18] final Maintenance, repair and overhaul carried out in december 2017, with the cost of 127 million rubles[19].

Operating speed limit has been a key for longevity and maintenance of the tunnel .[20] A new toll road, the central section of which is still under construction, will soon provide a north-south corridor over the island.[21]