ABSTRACT
The part of the under construction Egnatia highway, that crosses Pindos mountain-range (W. Greece), can be characterized as one of the most difficult parts for the construction, because of the high reief, the mountain slopes are steep and the flysch, which is the dominating geological formation in the area causes important landslides, occurred almost from the beginning of the road construction. According to our investigation the more important landslides occurred in the area are due: 1. to the geometry and the activity of the discontinuities (faults and important joints). 2. to the nature of the tectonic formation that lies under the Pindos nappes overthrusting the Ionian flysch (on the west of Metsovo tunnel), 3. to the nature of the tectonic formation that lies under the ophiolites overlying the Pindos flysch (on the East of Metsovo tunnel). These "tectonic formations" consist of silt-stones and pelites, containing detached blocks of limestones and deep sea sediments. Mechanically the above materials behave differently in dry and in wet conditions. In dry conditions they behave like a rock, while in wet conditions they loose repidly their cohesion and their original structure behaving like a sutured soil causing landslides along an important part of the road.
