ABSTRACT
Istanbul is a very fast developing city with more than 14 millions of population. Tunnelling activities like metro, sewerage and water tunnels are increasing tremendously and at the end of 2009 it is planned that around 23 TBMs with different diameters will be working in the city. The total cost of the current tunnelling projects is calculated to be around 20 Billion US Dollars. The geology of Istanbul is complex for tunnelling projects due to tectonic activities, faults, dacite and andesite dykes and several joint sets causing many serious problems during tunnel excavations. A great effort is spent by the authors of this paper to collect data concerning the performance of mechanized excavation systems related to geology and rock mass properties in order to have guidelines for the future tunnel projects.
