Numerical evaluation of slope effect on soil-pile interaction in seismic analysis

Abstract

This study aims to evaluate the slope effect on the behavior of soil-pile interface in the lateral direction, which is a factor governing the seismic response of pile-supported structures. A series of numerical simulations of a single pile in cohesionless soil subjected to lateral loading were performed by considering various slope configurations, soil densities, and loading directions. The lateral and confining forces acting at the soil-pile interface increased at a comparable rate under increasingly lateral loading. The ratio of the ultimate lateral force to the ultimate confining force was defined as a lateral interface-force ratio, which was introduced to quantify the slope effect on the strength parameter of the lateral soil-pile interface. The lateral interface-force ratio increased together with embedment depth and maintained a constant value below a certain depth corresponding to the change in failure mechanism from the wedge mode to the flow mode. In addition, an interface model of the soil-pile separation due to the slope failure was developed for the numerical analysis of piles in the cohesionless soil. Finally, the proposed lateral soil-pile interface was implemented via a three-dimensional numerical simulation of a dynamic centrifuge test for the validation work. The good agreement between the numerical simulation and experimental data indicates the reasonable applicability of the proposed interface properties.