Assessment of liquefaction triggering: The UBC3D-PLM constitutive model versus semi-empirical methods based on SPT-N values

Liquefaction is one of the main causes of deformation in medium- to low-density sand deposits in highly seismic zones. Due to the high cost of obtaining unaltered sand samples, the liquefaction potential is commonly determined through semi-empirical methods in terms of the N-SPT. Numerical modelling is a complementary analysis tool that, together with a constitutive model such as UBC3D-PLM, allows liquefaction in sands to be evaluated under different conditions. In this study, the cyclic resistance ratios of sands of different densities were determined using semi-empirical methods and numerical modelling. The modelling was performed with the UBC3D-PLM model using a 'user material' subroutine in the Plaxis 2D software package. Based on the results, a comparative analysis of the different methods was carried out and a good fit of the UBC3D-PLM model to historical liquefaction records was observed.