Associate Professor, Department of Civil, Energy, Environmental and Material Engineering, University Mediterranea of Reggio Calabria, Italy

Dr. Daniela D. Porcino is Associate Professor in Geotechnical Engineering at University "Mediterranea" of Reggio Calabria, Italy (Department of Civil, Energy, Environmental and Material Engineering. In December, 2017 she obtained the National Scientific Qualification to function as Full Professor in Geotechnical Engineering. She got her PhD in Geotechnical Engineering in 2002 presenting a PhD thesis titled: "Liquefaction study for coarse sand by laboratory investigation on undisturbed samples recovered by in-situ ground freezing technique". In 2009 she was awarded the "2009 best paper award" by the Prize Panel of "Geomechanics and Geoengineering: An International Journal". She has been head of several research contracts and, presently, she is scientific principal investigator a national multi- disciplinary research project granted in 2017. From November 2012 to December, 2014 she was member of the scientific Working Group appointed by the Emilia Romagna Region (Italy), to study remedial measures against liquefaction problems caused by 2012 strong earthquake occurred in Italy. Since 2002, she has published approximately 60 international journal articles and conference papers. Her main research interests concern, among others, cyclic liquefaction potential of complex soils (low plasticity silty sands, calcareous sands, cemented sands) through in situ and laboratory tests, cyclic pore water pressure generation models for clean sands and low plasticity silty sands from simple shear tests, and improvement of mechanical and hydraulic characteristics of sands through silicate grout.

Speech Title: Pore water pressure and liquefaction characteristics of low plasticity silty sands subjected to cyclic loading

Abstract: Sand-silt mixtures of low plasticity are very common in Italy either in natural depositional environment or in man-made earth-fill, hence the knowledge of their behavior is a crucial aspect in many practical applications. Due to higher compressibility features, significant strains and strength loss may be triggered by earthquakes.
Lessons learned from a recent laboratory investigation undertaken on undisturbed samples of low plasticity silty- sandy soils recovered from a bank stretch in the Emilia Romagna region (Italy) after the strong earthquake occurred in May 2012, when serious damages and widespread liquefaction events were observed, are described with special emphasis on susceptibility to liquefaction and pore water pressure response in presence of a static driving shear stress resulting from the bank slopes.
In the last part of the work, the results of undrained cyclic simple shear (CSS) tests carried out on reconstituted specimens of sand-silt mixtures were presented and discussed, Test program covered different fines contents in the range between 0 and 40%, void ratio and effective vertical stress at start of shearing. The conceptual framework based on equivalent granular void ratio appears appropriate for streamlining the effect of fines in non plastic or low plasticity silty sands and predicting cyclic liquefaction resistance of these soils, provided that fines content is less than a limiting value. Since an important stage in the assessment of liquefaction potential is to predict excess pore water pressure during cyclic loading, the results of CSS tests were also utilized for analysing pore water pressure generation models in low plasticity silty sands.