Seismic Analysis of Pile Foundation Passing Through Liquefiable Soil

In soil-pile-structure interaction non-linearity of soil plays very important role. The problem is furthermore complex when the piles are passing through liquefiable soil medium. In practice, for obtaining the internal response of soil-pile subjected to Seismic loading, many researchers and geotechnical engineers have used simple methods. In this paper a simple program based on Finite-element, i.e. “SAP2000” is propounded to examine the influence of seismic loading on deflection and bending moment of laterally loaded piles passing through liquefiable soil. In SAP2000, to simulate soil-pile interaction “Beam on Non-linear Winkler Foundation (BNWF)” model is used. In BNWF model, piles are modelled as a beam element and the surrounding soil is modelled as spring element. 3 × 3 pile groups in liquefiable and non-liquefiable soil are considered and a parametric study is carried out to analyse their seismic behaviour. The influence of different ratios of depth of pile to depth of liquefiable soil layer and effect of stiffness of the soil on the seismic behaviour of the soil-pile system are examined. Response spectrum and time histories are applied to analyse the response of pile during earthquake.