Seismic response comparison and sensitivity analysis of pile foundation in liquefiable and non-liquefiable soils

Case history investigations have shown that pile foundations are more critically damaged in liquefiable soils than non-liquefiable soils. This study examines the differences in seismic response of pile foundations in liquefiable and non-liquefiable soils and their sensitivity to numerical model parameters. A two-dimensional finite element(FE) model is developed to simulate the experiment of a single pile foundation centrifuge in liquefiable soil subjected to earthquake motions and is validated against real-world test results. The differences in soil-pile seismic response of liquefiable and non-liquefiable soils are explored. Specifically, the first-order second-moment method(FOSM) is used for sensitivity analysis of the seismic response. The results show significant differences in seismic response for a soil-pile system between liquefiable and nonliquefiable soil. The seismic responses are found to be significantly larger in liquefiable soil than in non-liquefiable soil. Moreover, the pile bending moment was mainly affected by the kinematic effect in liquefiable soil, while the inertial effect was more significant in non-liquefiable soil. The controlling parameters of seismic response were PGA, soil density, and friction angle in liquefiable soil, while the pile bending moment was mainly controlled by PGA, the friction angle of soil, and shear modulus of loose sand in non-liquefiable soil.