ABSTRACT
Out of the 75 dual motorway tunnels of the Egnatia highway project in northern Greece (Macedonia) two tunnels, Anthochori and Driskos, have experienced deformations and overstressing in their primary support associated with excavation in squeezing ground. This paper describes briefly the design guidelines for the Egnatia highway bored tunnels and presents the experience acquired during the design and construction of Anthochori and Driskos tunnels. In the Anilion tunnel of the Egnatia highway, extremely squeezing ground conditions are anticipated. The support designed to overcome the difficult ground conditions in this tunnel is a yielding temporary support system consisting of shotcrete and lattice girders with sliding joints. The final cast concrete lining is to be constructed after the anticipated deformations have stopped.
