Effects of Material and Geometric Nonlinearities on Seismic Soil-Pile Interaction in Liquefiable Soils

Abstract

Seismic performance of bridge abutments founded in potentially liquefiable soils is of significant interest to researcher and practitioners in geotechnical earthquake engineering. Piles are typically a key element of these geo-structures and may undergo large deformations and rotations when their lateral support is significantly reduced or momentarily lost due to the occurrence of earthquake-induced soil liquefaction. Observations from the past earthquakes show that in addition to material nonlinearity, geometric nonlinearity of the pile may also play an important role in the overall response of the foundation. In this work, a series of finite element analyses are carried out to assess the effects of material and geometric nonlinearities on the response of a pile embedded in liquefiable soil. The results of these numerical simulations are compared with the responses observed in the centrifuge experiments, performed at Kyoto University, modeling the same boundary value problem in Toyoura sand. The constitutive model used in the simulations is calibrated against a series of cyclic direct simple shear (CDSS) tests conducted at the George Washington University on Toyoura sand. The simulation results demonstrate that in addition to material nonlinearity of the pile material, geometric nonlinearity plays a critical role in modeling of the pile response, and without proper consideration of these effect, the overall response of the pile will not be accurately represented by the numerical simulations.