Development and Use of a Minicone for Liquefaction Risk Evaluation in Layered Soil Deposits

Abstract

This paper shows and compares the experimental results obtained by using a standard cone (10 cm2) and a mini piezocone (2 cm2). Tests were carried out at Calendasco (Piacenza, Italy) in a natural soil deposit mainly consisting of clayey-sandy silts. Grain size distribution with depth was also available. Other tests were carried out at Cavezzo (Modena, Italy), where liquefaction-induced phenomena were observed during the May 29, 2012, seismic sequence. The purpose was to investigate capabilities and limitations of mini piezocone and to explore the possibility of obtaining a better prediction of soil stratigraphy in thin layered deposits. Systematic differences in terms of tip resistance and sleeve friction were not observed, even though, generally, qc standard <qc mini. The spatial heterogeneity was considered responsible of the higher observed differences. In both test sites thin sandy layers are characterized by Ic mini ≤Ic standard, with a ratio of the Ic index as low as 0.88. This allows us to conclude that the minicone could be a valid alternative to the standard in identifying thin sandy layers.