ABSTRACT
Soil liquefaction is a phenomenon that typically occurs following earthquakes, although it may also be triggered by non-seismic loading. During liquefaction, a substantial and rapid reduction in the strength and stiffness of soils occurs due to pore pressure generation. Soil liquefaction is systematically investigated in the laboratory using element and model tests; however, certain aspects that prove critical in field liquefaction (e.g., soil fabric, dynamic loading, drainage conditions, and ageing effects) are challenging to reproduce in the laboratory. This has prompted researchers to investigate liquefaction directly in the field by means of blast tests, i.e., experiments in which liquefaction is induced by controlled explosive detonations.
Numerical simulation is nowadays frequently employed to simulate the onset and development of soil liquefaction. In this context, the primary objective of the present study is the numerical simulation of a controlled blast-induced liquefaction test conducted at a silty sand site in Bondeno, Ferrara, Italy. To this end, a constitutive model named CASM-SM has been implemented to reproduce soil behaviour during cyclic loading, having been recast within a subloading plasticity framework. The modelling of soil behaviour under blast loading is challenging due to several factors, including the characteristics of soil deformation close to the explosive, soil stiffness degradation, high frequencies in acceleration records (exceeding 100 Hz), and a significant increase of excess pore water pressure over a short timeframe (on the order of milliseconds). The Bondeno blast test simulation served as an excellent platform for validating the performance of the CASM-SM model. Particular attention was paid to the reproduction of the acceleration records, as well as velocities, Arias intensity, Fourier spectra, and spectral acceleration. Moreover, excess pore water pressures were compared against pore pressure transducer data. The results obtained from the numerical simulation provide relevant insights into blast-induced liquefaction within the silty sand layer.
PhD Advisors:
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- Prof Marcos Arroyo
- Prof Antonio Gens
SPEAKER
Paul José Pinedo is a PhD candidate in Geotechnical engineering in CIMNE’s Geomechanics and Hydrogeology research clúster.