The Saimaa crossing

«Stroygasmontazh» has completed the construction of an underground crossing under the Saimaa channel at the Gryazovets — Vyborg gas pipeline. The work was conducted in difficult geological conditions, using special equipment.

Ecologically safe option	Start up site	Drilling rate is 6 m per day
Tunneling shield at the exit of the tunnel	The first of five strings are fed into the tunnel	Ground way

Vadim Khodosov, Deputy Director General, LLC “Tonnelniy otryad-4”

— The construction of the crossing across the Saimaa Channel was quite a difficult task, since nobody in the world had ever done such micro-tunnels in the rock. It is not surprising that we had to enter changes to the project three times. Moreover, in the course of works there were a number of off-nominal situations. For example, at the time of passing the entry pit at the depth of 13 meters, we came upon a quicksand, and when we reached the rock, it turned out that we could not avoid blasting works here as well. Nevertheless, all the difficulties were overcome, and the tunnel was completed.

In my opinion, it was possible thanks to the coherent cooperation of all the parties involved. We met understanding, support of our position in the resolution of any issues: financial, technical decisions, construction deadlines. Everybody helped us in LLC «SGM», from Anatoly Evseev, Yaroslav Soga, Victor Kolesnik to Alexander Tarasov, as well as in OJSC «Krasnodargazstroy», here it is worth noting Andrey Andreev and Nikolay Bulatov. It’s nice to know, that people have a sense of responsibility when working with contractors.

Now we are preparing to work on the second phase of the pipeline. Five more micro-tunnels are to be built, including crossings under the rivers Sheksna (of 700–800 m), Volkhov (980 m, it is near Kirishi town), and under the Neva and the Saimaa Channel. So in order to cross the Volkhov, we will need a new shield, able to work on the limestone rocks. Right now, together with the German company Herrenknecht AG, we are manufacturing it and hope that by the end of this year it will be ready.