The tunneling rig Soilmec ST-120 has played a key role in the construction of a new underpass in Sochi. After 22 months of digging works for the double tunnel T8 and T8A, works were finally completed on December 27th, 2013, and it was opened to traffic in time for the Olympic Winter Games.
Soilmec has sold to Transstroy a package of special equipment including 4 dual-arm ST-120 drilling rigs (commonly called positioners) for consolidation works in the gallery for the new T8 and T8A tunnels construction in Sochi. The Russian Federation has taken the opportunity offered by the accomplishment of these important works in order to test the most innovative and promising technologies existing in the world with regard to underground excavation.
In this perspective, the Russian Federation has accepted the proposal of Prof. Pietro Lunardi of Rocksoil S.p.A. to design and build the tunnels T8 and T8A within the “Dubler Kurortnogo Prospekta” (the longest and most complex tunnels of the ring road in Sochi) according to the principles pertaining to the approach of ADECO-RS through which, between 2000 and 2010, in Italy, over 100 km of tunnels for the high speed/capacity railway line between Bologna and Florence were built, complying with the time and cost planned.
Following this decision, the Russian Federation has appointed the same Rocksoil S.p.A. to draw up the construction project and then provide the necessary technical assistance on site during construction. Among the various tunnels constructed for the bypass, the galleries T8 and T8A were quite challenging due to the extreme difficulty of the geological context in which works had to be performed, to the length of the track underground (1,550 m for the gallery T8 and 1,523 m for the gallery T8A) and to the size of the excavation sections which vary from 120 m2 to 220 m2. The cover on the tunnel cap reaches 75 m in the northern sector, but it is low on the average and within a heavily urbanized environment.