Influence of soil–pile interface characteristics on the seismic response of single pile foundations: shaking table testing and numerical simulation

Soil–pile interface conditions during seismic events could cause a severe impact on the response of deep foundations which is not fully addressed in the previous contributions. To answer some practical questions, a series of small-scale shaking table model tests were first performed to study the seismic response of fixed-head single piles in dry sand subjected to sinusoidal waves with constant frequency under wide acceleration amplitudes. The physical modeling results then were followed by a nonlinear three-dimensional numerical simulation and adequately verified. The numerical study was subsequently extended to gain further insight into the effect of the soil–pile interface on the seismic response of single piles. For this purpose, the effects of slippage and/or separation on the acceleration response of the pile cap as well as the normalized seismic forces in the pile are discussed under different pile head and soil profile conditions. Extracted results showed that in some cases, piles experienced 100% larger forces due to soil–pile interface conditions.