Liquefaction potential evaluation of intermediate soils from mechanical and electrical CPT’s. The case study of Barberino di Mugello (Italy)

Different CPT-based methods generally provide considerably different liquefaction potential values if they are applied to these soil mixtures of sandy silts to clayey sands and they often fail if the fine content and its plasticity are not known. Moreover, in several countries including Italy, most of the CPTs available for large scale studies (e.g. seismic microzonation) are mechanical; thus, the sleeve friction, especially if the fine content is high, can be affected by errors and lead to erroneous soil classification. Therefore, the simplified methods, which are based on electrical CPT measurements, can lead to erroneous estimates of liquefaction resistance and to considerably non-conservative results, if they are applied to mechanical CPT data without any form of correction. The present paper aims to compare three different CPT-based simplified methods for assessing the liquefaction potential of intermediate soil deposits in the municipality of Barberino di Mugello (Italy).