ABSTRACT
The Project Extension of the Sofia metro (Bulgaria), Line 3, phase I, aims to build almost 8 km of new line and 7 new stations. Main tunnel consists in a metro single tube configuration excavated by an EPB Machine. In order to minimize interferences with other contractors involved in the project, new intermediate site establishment to operate the TBM was planned. To maintain original TBM logistic concept, 2 temporary connection from surface to the tunnel where designed: a vertical shaft over the tunnel section, to proceed with the precast segments and other tunnel material supply; Lateral shaft with a ramp to the surface including 2 lateral connections to the main tunnel in order to manage the TBM belt conveyor and transfer out the excavated material. Planning the overall tunnel execution, logistic TBM shaft concept design and TBM performance analysis from each site establishments are presented.
