Construction of the Maly Novorossiysky tunnel

The project name is the Maly Novorossiysky tunnel of the North Caucasian railway. This project includes construction of the new double-track tunnel (running parallel to the existing one) and conservation of the old existing tunnel. The Maly Novorossiysky tunnel is located between Tonnelnaya and Gaiduk stations in the Krymskaya – Novorossiysk section of the North Caucasian railway.

The old tunnel length is 389,3 m. It was constructed in 1885 – 1887. The tunnel has two tracks of old standard - 1524 mm with the intertrack space of 3753 mm without taking into account widening on curve. This tunnel is planned for conservation.

Construction of the new tunnel started from the south portal. The tunnel was excavated using benching method by means of roadheaders Mitsui S-200. The upper and lower benches were excavated simultaneously with the difference of 150 running meters. To concrete the tunnel permanent lining (vault and walls) a metal formwork «Vartington» movable on rails was used. The invert was concreted 80 -100 meters after.

An open section of 43 meters was excavated by cut-and -cover from the south portal. This cut-and-cover section was supported by secant piles.

After the new double – track tunnel is commissioned and all traffic is focused on this tunnel, the old tunnel will be repaired. The repair works include:

• disassembly of the track and concreting of the invert;
• repairs of the lining in broken points;
• drilling the drain holes out where water leakage is heavy;
• shotcreting of the existing lining.