Critical buckling load of pile in liquefied soil

Buckling instability has been recently identified as a possible mechanism of pile failure in liquefiable deposits and this failure mechanism is not explicitly mentioned in most design codes. To carry out routine design and checking, it is necessary to reliably estimate the critical buckling load of pile for a given liquefiable site. However, the existing calculation methods for the critical buckling load of pile in liquefied soils do not consider the influence of geometric imperfections and nonlinear behavior of the pile. In this paper, an efficient approach using the Beam on Nonlinear Winkler Foundation (BNWF) model is proposed to calculate the critical buckling load of pile in liquefied soils considering geometric imperfections and nonlinear behavior of the pile. The method is verified and validated using the finite element method and results from centrifuge tests. Furthermore, parametric analysis has been carried out to understand the influence of buckling load for different soil relative density, initial geometric imperfections of pile, flexural rigidity of pile, and pier height. It is found that the critical buckling load of pile in liquefied soils increases with the increase of soil relative density and flexural rigidity of pile, and decreases with the increase of initial geometric imperfections of pile and pier height. Finally, a simplified estimation method based on Euler buckling theory is provided for predicting critical buckling load of pile in liquefied soils and an example is taken to show the application.