3RO North, section 2, Velenje - Slovenj Gradec, geological-geomechanical investigations
Investment value: € 400 mio
Our role: Investigation management, responsible engineering geologist, responsible designers of studies
Year of the design of technical documentation: 2010-2021
The investigated section is 18.38 km long. Several structures are planned along the expressway, the link road and the deviations: 3 tunnels, 2 cut and covers and 17 viaducts, 7 bridges, 4 overpasses, 6 underpasses, 40 culverts, excavations and embankments. In order to protect the slopes there are 43 support walls and 22 retaining walls planned. The geological and geotechnical conditions in the area are very changing. The route crosses the sediments of the Slovenjgrad Fault, the Miocene sediments of the rocks of the Eastern Alps, the Palaeogene tonalite, the carbonate rocks of the Southern Alps and the sediments of the Velenje Fault.
The investigations included an engineering-geological and hydrogeological survey of the terrain, the drilling of 400 boreholes, 320 exploratory excavations, 210 dynamic or static penetrations, 75 piezometers in which hydrogeological investigations were carried out, laboratory investigations on 3900 samples, and the preparation of geological-geomechanical studies for the route, the viaducts, the tunnels and other structures.