ABSTRACT
This paper presents an adopted methodology for Tunnel Boring Machine (TBM) selection, based on the results of engineering geological - geotechnical feasibility assessment of tunnels. The selection of the appropriate TBM is analysed and presented step by step, addressing all issues that cover most engineering geological and geotechnical critical aspects of the selection process. The applicability of each type of TBM is discussed using a significant number of sampling boreholes and in situ - laboratory testing, obtained from an extensive ground investigation campaign, in urban environment. This information was elaborated in order to obtain a better engineering geological understanding and ground zonation with respect to mechanised tunnelling. Besides the expected geomaterial behaviour, the TBM selection is also based on the percentage of fines at the tunnel profile, the permeability and hydraulic head, while abrasiveness, sticky behaviour, clogging risk and mixed ground conditions are also taken into account. Finally, an example of the application of TBM type selection methodology in urban tunnel is given.
