Single Piles in Liquefiable Ground: Seismic Response and Numerical Analysis Methods

This thesis focuses on the seismic response of piles in liquefiable ground. It describes the design of a three-dimensional, unified plasticity model for large post-liquefaction shear deformation of sand, formulated and implemented for parallel computing. It also presents a three-dimensional, dynamic finite element analysis method for piles in liquefiable ground, developed on the basis of this model,. Employing a combination of case analysis, centrifuge shaking table experiments and numerical simulations using the proposed methods, it demonstrates the seismic response patterns of single piles in liquefiable ground. These include basic force-resistance mode, kinematic and inertial interaction coupling mechanism and major influence factors. It also discusses a beam on the nonlinear Winkler foundation (BNWF) solution and a modified neutral plane solution developed and validated using centrifuge experiments for piles in consolidating and reconsolidating ground. Lastly, it studies axial pileforce and settlement during post-earthquake reconsolidation, showing pile axial force to be  irrelevant in the reconsolidation process, while settlement is process dependent.