Twin bore at Biakal for Siberian Silk Road railway 09 Aug 2018

Russia has completed excavation of a parallel tube for the existing Baikal Tunnel on the BAM (Baikal-Amur Mainline) railway in Russia, traversing Eastern Siberia and the Far East of the country. Baikal is the second tunnel on the long Trans-Siberian route after the 15.3km long Severomuiski single-tube bi-directional single-track tunnel, which took 27 years to excavate through exceedingly difficult geological conditions (Fig 1).

Fig 1. BAM rail route across Siberia with locations of the Baikal and Severomuiski Tunnels

Opening of the parallel tube for the 6.7km Baikal Tunnel in 2019 will double its capacity and increase freight traffic on the route by two and a half times to 32 million tonne of cargo per year. The increased capacity will be vital to the role of BAM as part of the New Silk Road project that will deliver Asian cargo by rail to Europe across the territory of Russia.

Located on the border of the Irkutsk region and Buryatia, the twin tubes of the Baikal Tunnel passes through the Baikal Range under the Davan Pass, an area characterized by high seismic activity of up to 8 and 9 on the earthquake Richter scale. The tunnel passes through rocky ground intersected by numerous tectonic zones. The new tunnel passes 35m to the left of the existing tunnel, construction of which was completed in late 1985. Official opening of the new tunnel is scheduled for 2019.

Construction site of the Baikal Tunnel parallel drive

Construction of the parallel tunnel has a strategic importance for Russia, as it will solve a severe bottleneck for train traffic on the BAM railway. The Russian Government has been planning to modernize the BAM and the Trans-Siberian Railways for several years. Since the 2000s, railway infrastructure across Siberia has barely coped with the ever-growing freight train traffic generated by the New Silk Road rail route from Asia to Europe. Construction of the parallel Baikal Tunnel tube began in the Autumn of 2014.

The project was implemented by the SK Most Group of Companies, one of Russia’s largest tunnel builders.

According to First Deputy General Director Vladimir Gartig of Bamtonnelstroy, part of the SK Most Group and a contractor on the project, rock strengths for the geology along the alignment were not the highest, and were estimated in places at only 8 to 10 units on the units of the Protodyakonov scale. Complex geological conditions presented several difficulties during tunnel excavation that were overcome by the mechanized and drill+blast methods employed.

At 15.3km long, the Severomuiski Tunnel is a single-tube, single-track, bi-directional tunnel with no plans as yet for its duplication after major challenges during excavation of the original pilot and main tunnel excavations

“For excavation, we used a refurbished Lovat TBM and drill+blast operation for portals and cross connections from the new tunnel to the existing parallel tube,” explained Gartig. Muck hauling from behind the TBM used a fleet of special industrial vehicles, a kind of Belarus BelAz, which transported material to disposal sites.

Dmitry Peskov, a spokesman for Russian President Vladimir Putin, who personally controlled implementation of the project, said, “to date, the Baikal Tunnel has been one the most problematic sections on the entire railway infrastructure across Siberia. Further increase of cargo flows on this BAM route was impossible without double-track train operations through the Baikal Range. The new Baikal Tunnel will double the capacity of the Severobaikalsk-Lena section and ensure the development of promising railroads on the northern route of the East Siberian Railway.”

Excavation of the parallel tube was carried out using the Lovat RM-394DS TBM that was employed initially for excavation of transportation tunnels in the Black Sea city of Sochi to prepare for the Winter Olympic Games of 2014.

Establishing the portal for the parallel Baikal Tunnel TBM drive

According to a spokesman of SK Most, the Lovat TBM achieved advance rates of 12m/day and was not inferior to the Herrenknecht TBM that was used to excavate the Lefortovo highway tunnel in Moscow.

“This double shield TBM features a powerful cutterhead drive, a high thrust gripper assembly and erected a high-strength reinforced concrete segmental lining as it progressed,” said the SK Most representative. Construction involved more than 1,200 people and more than 100 units of mining and construction equipment, as well as road machines and vehicles.

With TBM tunnelling complete, SK Most continues excavation of the eastern and western drainage tunnels of 1,700m and 1,500m respectively using excavator machines for open face excavation method. There are also plans to complete excavation of two escape galleries of 232m each.

Successful TBM excavation of the parallel tube of the Baikal Tunnel is expected to accelerate implementation of some strategically important tunneling projects for the Russian economy, and in particular the construction of the Siberia Power gas pipeline.