Numerical analysis of pile-soil system under seismic liquefaction

This study considers the motion of an end bearing single pile with lumped mass embedded in sandy soil deposit subjected to seismic liquefaction. An efficient finite difference model, whose accuracy was validated through experimental results, has been constructed to study the dynamic responses of piles under liquefaction. Effects of parameters such as soil and pile properties, and predominant frequency on the dynamic response of pile are examined. Results reveal that earthquake predominant frequency, pile stiffness, soil relative density and soil-pile relative stiffness, can significantly affect the pile's dynamic response, while pile material densities have negligible effects. Final results demonstrate that with increasing in pile stiffness, soil relative density and soil-pile relative stiffness, maximum moments in piles are increased while with increasing the earthquake predominant frequency, maximum moments in piles and depth of the liquefaction are reduced. Also, the depth in which the maximum value of the moment, Mmax, occurs, depends only on the pile stiffness.