ABSTRACT
A tunnel network consisting of three single tube tunnels which have been projected based on New Austrian Tunneling Method (NATM) in Istanbul. The tunnels were excavated in Sandstone (very poor - poor strength), Quartzite (fair - good strength) and Arkose (very poor - poor strength). Tunnels are passing very shallow under residential areas especially at the entrance and exit parts of the tubes. In this paper, the main points of the tunnel design and construction will be explained and the measurements made at the site during the construction will be shown. These monitoring data will be compared with the numerical analysis results obtained during the design phase.
