Influence of liquefaction on pile-soil interaction in vertical vibration

摘要

During strong earthquake shaking, loose cohesionless soils below the water table develop high pore water pressures and liquefy leading to significant degradation of strength and stiffness. In such soil stratum, pile foundations may undergo substantial shaking while the soil is in a fully liquefied state and soil stiffness is at its minimum. In this paper, an available numerical model formulating the pore pressure response directly from observed data on undrained tests has been used to study the liquefaction phenomenon. The Winkler soil model has been used to model the pile-soil interaction. Combining these two models, a formulation to predict the response of a pile in liquefiable soils in axial vibration is developed. It is observed that the response of a single pile due to axial vibration in liquefiable soil is significantly greater than that in non-liquefiable soil, particularly at higher frequencies.