Development of Simplified Analysis Procedure for Piles in Laterally Spreading Layered Soils.

摘要

This work presents the development of a simplified procedure for the analysis of liquefaction induced lateral spreading using a beam on nonlinear Winkler foundation approach. A three-dimensional finite element model, considering a single pile in a soil continuum, is used to simulate lateral spreading and two alternative lateral load cases. Sets of p-y curves representative of the soil response in the 3D model are computed for various soil-pile systems. The affects of pile kinematics on these curves are evaluated and a computational procedure for p-y curves is proposed. The computed curves are compared to p-y curves defined by existing methods commonly used in practice to evaluate the applicability of these methods to lateral spreading analysis. Comparison of the p-y curves resulting from homogenous and layered soil profiles, in which a liquefied layer is located between two unliquefied layers, is used to identify reductions in the ultimate lateral resistance and initial stiffness of the p-y curves representing the unliquefied soil due to the presence of the liquefied layer. These reductions are characterized in terms an exponential decay model. A simple procedure utilizing dimensionless parameters is proposed as a means of implementing appropriate reductions for an arbitrary soil profile and pile diameter. Beam on nonlinear Winkler foundation analyses of lateral spreading are conducted to validate and demonstrate the use of the proposed reduction procedure.