Liquefaction susceptibility assessment based on in situ geotechnical and geophysical characterisation of a pilot site in the greater Lisbon area

• Type: Article in International Scientific Journal
• Date: 2020

Authors

António Viana da Fonseca (Author) FEUP; Cristiana Ferreira (Author) FEUP; Catarina Ramos (Author) Other; Ana Sofia Saldanha (Author) Other; Sara Amoroso (Author) Other; Carlos Rodrigues (Author) Other

Journal

Title: Bulletin of Earthquake Engineering

Vol. 18 No. 1

Pages: 109-138

ISSN: 1570-761X

Publisher: Springer Nature

Indexing

ISI Web of Knowledge - 15 Citations

ISI Web of Science

Scopus - 19 Citations

Other information

Authenticus ID: P-00R-76K

DOI: 10.1007/s10518-019-00721-1

Abstract (EN): In Portugal, particularly in the greater Lisbon area, there are widespread alluvial sandy deposits, which need to be carefully assessed in terms of liquefaction susceptibility and risk zonation. For this purpose, a pilot site has been set up, as part of the European H2020 LIQUEFACT project. An extensive database of geological and geotechnical reports was collected and a comprehensive site investigation campaign was carried out, including boreholes with standard penetration (SPT), piezocone penetrometer and seismic dilatometer tests as well as geophysical methods, complemented by undisturbed soil sampling for laboratory characterisation. The assessment of liquefaction susceptibility based on field tests was made using the simplified procedure, considering the factor of safety against liquefaction (FSliq), which relates the cyclic resistance ratio (CRR) with the cyclic stress ratio (CSR). While the computation of the CSR is relatively straightforward, the reliability of the CRR strongly depends on the adopted in situ testing technique. Alternative approaches to liquefaction assessment have been proposed, based on quantitative liquefaction damage indexes, namely the Liquefaction Potential Index (LPI) and Liquefaction Severity Number. In this paper, the geotechnical field data is integrated in these distinct approaches to liquefaction assessment. A comparative and in-depth analysis of the conventional approach is presented and the inclusion of specific information on soil type, as a means to overcome the observed differences, is discussed particularly for SPT and V-S results. The combination of these criteria enabled to clearly identify the most critical layers, in terms of liquefaction potential and severity.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 30