COMPORTAMENTO NON DRENATO DEI LIVELLI SABBIOSO-LIMOSI PRESENTI NELLE ALLUVIONI DEL FIUME TEVERE A ROMA (ITALIA) — IJEGE
 
 
You are here: Focus and scope Issues from 2005 to 2017 IJEGE 12 IJEGE 12 - Volume 02 COMPORTAMENTO NON DRENATO DEI LIVELLI SABBIOSO-LIMOSI PRESENTI NELLE ALLUVIONI DEL FIUME TEVERE A ROMA (ITALIA)
Document Actions

UNDRAINED BEHAVIOUR OF THE SANDY-SILTY LEVELS OF THE TIBER RIVER ALLUVIAL DEPOSITS IN ROME (ITALY)



Abstract:
This paper reports the findings from a laboratory study aimed at the physical and mechanical characterisation of sands belonging to recent Tiber river alluvia (level D Auct.) located in historical centre of Rome. The study was conducted in preparation for subsequent analysis of possible seismically-induced effects of permanent deformation and/or liquefaction under the worst expected seismic shaking scenarios. Tests were carried out on a laboratory-reconstituted granular mix, which was considered to be representative of the above deposits. This choice was justified by: i) the difficulty or impossibility of collecting fairly undisturbed samples with standard boring techniques, and ii) the need for gathering about 50 kg of material for all the planned tests. The tests consisted of: undrained static mechanical tests and dynamic resonant-column tests. They were conducted at the Laboratorio di Geologia Applicata - Dipartimento di Scienze della Terra-CERI, Sapienza University of Rome - and at the Laboratoire de Méchanique des Sols - Départment Géotechnique, Eau et Risque (IFSTTAR-Paris). The representativeness of the granular mix was assessed on the basis of the: i) mineralogical composition and the weight per unit of volume of the solid (γs), ii) comparison of its grain size with a target curve of the in-situ deposits, and iii) Unified Soil Classification System (USCS). The Proctor optimum of the granular mix was attained at a saturation of 90%, with a water content (w) of 17.6%, corresponding to a density (γd) of 16.70 kN/m3. Undrained strength - determined via unconsolidated undrained triaxal tests (TxUUI) - was in the range of 20 to 60 kPa for void ratio (e) values of 0.7 to 0.5, whereas the critical void ratio (ecr) values were comprised between 0.55 and 0.65, corresponding only in part to the ones obtainable for the in-situ deposits (0.6

Authors:
Francesca Bozzano - Sapienza Università di Roma - Dipartimento di Scienze della Terra - Rome, Italy
Alberto Bretschneider - Sapienza Università di Roma - Dipartimento di Scienze della Terra - Rome, Italy
Anna Chiara Giacomi - Sapienza Università di Roma - Dipartimento di Scienze della Terra - Rome, Italy
Luca Lenti - Institut Français des Sciences et Technologies des Transports, de l’Aménagement et des Réseaux (IFSTTAR-Paris)
Salvatore Martino - Sapienza Università di Roma - Dipartimento di Scienze della Terra - Rome, Italy
Gabriele Scarascia Mugnozza - Sapienza Università di Roma - Dipartimento di Scienze della Terra - Rome, Italy
Luigi Stedile - Sapienza Università di Roma - Centro di Ricerca CERI “Previsione, Prevenzione e Controllo dei Rischi Geologici” - Valmontone, Italy
Jean-Louis Tacita - Institut Français des Sciences et Technologies des Transports, de l’Aménagement et des Réseaux (IFSTTAR-Nantes)
Keywords
sandy-silty alluvia, unconsolidated undrained triaxial tests, resonant-column tests, dynamic properties, Rome
Statistics