ABSTRACT
The tunnel T8, which will be placed approximately 35 km east of Ioannina, will be part of the new Highway Egnatia Odos crossing the northern part of Greece in East-West direction. The subsoil the tunnel will be built in, is the Ionian Flysch consisting of conglomerates, sandstone and siltstone/shale. This Flysch was folded and scaled by East-West compression since the last orogenetic phase and is an inhomogeneous and complex subsoil for tunnelling. A comparison of the results of rock mass classification according to Bieniawski, Hoek and Marinos & Hoek will be presented. Also the differences in using an isotropic rock mass model or an anisotropic rock mass model for the static calculation will be shown. The proposed excavation classes for the tunnel construction are also prescribed in this paper. The tunnel T8 will be constructed by drill-and-blast method and the construction has just started.
