1. Professor, Faculty of Civil Engineering, Univ. of Maribor, Smetanova ulica 17, 2000 Maribor, SI-Slovenia (corresponding author).
2. Senior Lecturer, Faculty of Civil Engineering, Univ. of Maribor, Smetanova ulica 17, 2000 Maribor, SI-Slovenia.
3. Geological Survey of Slovenia, Dimičeva ulica 14, 1000 Ljubljana, SI-Slovenia.