Numerical Study on Dynamic Behavior of Pile Group in Liquefiable Soils

Abstract

The pile bending moments are particularly important for engineers to design pile foundations in liquefiable soils. In order to investigate the effect of width-tothickness ratio of pile cap, pile diameter, initial stiffness ratio of soil and pile and mass of superstructure on the pile peak bending moments subjected to dynamic loading, the three-dimensional (3D) finite difference method considering the coupling of soil-fluid is employed to simulate shaking table experiment for soil-pile group interaction in liquefiable soils under sinusoidal wave. For comparison, a representative single-pile reference simulation is also studied. In the numerical modeling, a modified form of the Mohr-Coulomb plasticity model called as Finn Model (Itasca, 2002) that can perform coupled dynamic-groundwater flow calculations is used to simulate the effects of soil liquefaction. The numerical modeling is well verified through the shaking table experiment. A number of results and discussions are presented for describing the simulated behavior of pile group in liquefiable soils. INTRODUCTION It is widely recognized from past earthquakes that site liquefaction has caused tremendous damages to bridge pile foundations. Understanding the performance of pile foundations in liquefiable soils is very important for minimizing losses during earthquake. According to the shaking table experiments, centrifuges, filed tests and numerical simulations, many studies have been conducted since the 1964 Niigata earthquake. As we all know, shaking table experiment is an effective tool for studying the dynamic responses of pile foundations in liquefiable soils. However,