Abstract
The tunneling technologies are constantly evolving, with the large diameter multifunctional city tunnels becoming more and more common. By building tunnels of large diameters in urban areas one can rationally distribute traffic flows within the unified space and combine various modes of transport. However, such scalable transport construction projects imply a serious pressure both on social aspects of the big cities life and on the city environment. So, in order to make a decision one needs to perform a comprehensive analysis. The authors have analyzed the foreign experience in large diameter tunneling to assess whether it is viable to use these kinds of structures under the geological conditions of St. Petersburg.