Numerical investigation on the principal stress rotation effect under earthquake loadings

Earthquake loadings can cause significant principal stress rotation (PSR) in the sand bed. Even the pure PSR (rotation of principal stress axis with constant principal stress magnitudes) can lead to the build-up of excess pore water pressures and accumulation of plastic strains, thus accelerating sand liquefaction in undrained conditions. This paper conducts the fully coupled finite element simulations of a centrifuge test to investigate the PSR effect under earthquake loadings. The PSR is considered by using a PSR model developed based on an elastoplastic sand model with kinematic hardening and bounding surface concepts. The numerical predictions from the PSR model and base model are compared with the experimental results. The comparative study shows that the PSR model performs better than the base model at capturing the sand responses and liquefactions behaviors. The investigation also finds obvious PSR in the sand bed and demonstrates the importance of considering the PSR effect under earthquake loadings in undrained conditions.