SPH simulation of earthquake-induced liquefaction and large deformation behaviour of granular materials using SANISAND constitutive model

Earthquake-induced liquefaction and consequent failure of geomaterials have been recognised as a geohazard that causes significant damage to geotechnical infrastructures. Predicting such large deformation events has proven to be a challenging topic, which requires the development of powerful numerical tools and advanced soil models. The Smoothed Particle Hydrodynamics (SPH) method has been successfully applied to simulate large deformations and post-failure processes of geotechnical problems, including seismic large deformation analyses. However, the SPH simulation of earthquake-induced liquefaction and large deformation of geotechnical problems remains challenging, primarily due to the lack of a stabilised computational framework capable of capturing the complex responses of soil liquefaction. This study addresses this research question with the developments and applications of a fully coupled flow-deformation SPH framework incorporating the SANISAND model for solving earthquake-induced liquefaction problems. Several stabilisation techniques, including Rayleigh damping, stress diffusion and pore-pressure diffusion, are introduced to improve the stability and accuracy of SPH simulations. Additionally, a robust stress update method, combining the sub-stepping technique and cutting-plane algorithm, is proposed to effectively integrate the constitutive laws of the SANISAND model during large deformation SPH simulations. Verification of the proposed SPH framework against theoretical solutions shows its effectiveness before being applied to simulate several shaking table tests reported in the literature. The proposed SPH framework and model are able to reproduce experimental results in several simulations, demonstrating their potential and capability for the future prediction of earthquake-induced liquefaction and failure of geo-infrastructures.