An SPH Framework for Earthquake-Induced Liquefaction Hazard Assessment of Geotechnical Structures

Earthquake-induced soil liquefaction poses significant risks to the stability of geotechnical structures worldwide. An understanding of the liquefaction triggering, and the post-failure large deformation behaviour is essential for designing resilient infrastructure. The present study develops a Smoothed Particle Hydrodynamics (SPH) framework for earthquake-induced liquefaction hazard assessment of geotechnical structures. The coupled flowdeformation behaviour of soils subjected to cyclic loading is described using the PM4Sand model implemented in a three-phase, single-layer SPH framework. A staggered discretisation scheme based on the stress particle SPH approach is adopted to minimise numerical inaccuracies caused by zero-energy modes and tensile instability. Further, non-reflecting boundary conditions for seismic analysis of semi-infinite soil domains using the SPH method are proposed. The numerical framework is employed for the analysis of cyclic direct simple shear test, seismic analysis of a level ground site, and liquefaction-induced failure of the Lower San Fernando Dam. Satisfactory agreement for liquefaction triggering and post-failure behaviour demonstrates that the SPH framework can be utilised to assess the effect of seismic loading on field-scale geotechnical structures. The present study also serves as the basis for future advancements of the SPH method for applications related to earthquake geotechnical engineering.