Severomuysky Tunnel is a railroad tunnel on the Baikal Amur Mainline (BAM), in northwestern Buryatia, Russia. It is named after the Severomuysky Range it cuts through. The tunnel is 15,343 metres (50,338 ft) long, the longest in Russia (excluding metro lines).
The tunnel cuts under the Severomuysky Range, a mountain ridge separating the Upper Angara basin to the north west from the Muya basin to the south east. The BAM then follows the valley of the Muyakan River on its way east towards its junction with the Muya shortly before Taksimo. A works town named after the tunnel was built at each end during its construction; Tonnelny at the western portal and Severomuysk at the eastern portal. Tonnelny was abandoned in 2004 after the opening of the tunnel and its population relocated to Severomuysk. Employment in Severomuysk relies almost entirely on the maintenance of the tunnel and its bypass route.
Its construction was carried out in a completely uninhabited edge with harsh climatic conditions and in the constant earthquakes (seismicity of the area 9 points).
On the construction of a tunnel tested construction machinery and vehicles from ten countries. Only for the main production processes used by more than 850 pieces of equipment.
Severomuisky tunnel – a unique piece of engineering for many indicators of its existence, design and construction. It is 40.5 km mining, 1.5 million cubic meters of dredged material, 700 thousand cubic meters of reinforced concrete, 55,345 mounted cast iron tubing, 70 tonnes of metal.
Unusual geotechnical conditions, the presence of a large number of tectonic faults, different structure, extent, water cut, demanded changes in the way of penetration along the length of the route of the tunnel.
During construction of the tunnel were mastered technologies:
penetration mechanized complexes Tunnel diameters of 4.5 and 5.6 m firms Robbins (USA) and Wirth (Germany), as well as domestic shields diameter up to 9.7 m;
speed of penetration mining method in a wide range of mining and hydrogeological conditions in the rocks by a factor of 0.6-2 fortress to 14-18 (on Protodiakonov) using high-performance rigs section to 56 m2 firms Furukawa (Japan), Tamrock (Finland) ;
Construction of concrete lining in tunnels using mechanized formwork section up to 60 m2 firm Saga Kogio (Japan);
vertical and horizontal drilling dewatering by the length of 500 m;
application of seismic and heat-resistant double-layer tunnel lining;
the methods for rapid penetration in different geological conditions.
To expand the front tunnel works and permanent ventilation devices during the operation of the tunnel was constructed four mine shafts with depths ranging from 170 to 350 m
During the construction of the tunnel was developed and applied technology chemical grouting unstable soils in zones of tectonic faults.
First in social practice has been developed and implemented an automated process control system (PCS) during construction.
March 30, 2001 took place sequentially, “golden” sboyka tunnel divergence axes colliding faces was only 13 mm, 317 mm at permitted.
With the opening of the tunnel, the time required for a train to cross the section has been reduced to only 15 minutes. However, the 54 km long bypass is still sometimes used for goods traffic to allow other trains to pass through the single-track tunnel. The opening of the tunnel also allowed 6 million tons of freight annually to be switched onto the BAM from the Trans-Siberian Railway.