Publication Date:
2023-10-24
Description:
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 VS
results. The combination
of these criteria enabled to clearly identify the most critical layers, in terms of liquefaction
potential and severity.
Description:
Published
Description:
109-138
Description:
5T. Sismologia, geofisica e geologia per l'ingegneria sismica
Description:
JCR Journal
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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