1. Assistant Professor, Dept. of Structural and Geotechnical Engineering, Univ. of Rome ‘La Sapienza’, Via Eudossiana 18. 00184 Roma, Italy. (corresponding author).
2. Assistant Professor, Dept. of Geoengineering and Environmental Technologies, Univ. of Cagliari, Piazza d’Armi, 09123 Cagliari, Italy.