PERTURBATION ANALYSIS OF PILE'S POSTBUCKLING

It is of significant meanings to study the post-buckling equilibrium path of an axially loaded pile embedded partially in soil, for the long slender pile can fail in buckling mode, especially in soft soil. The non-linear large deflection differential equation of the pinned pile was established by energy method firstly. Then, the non-linear large deflection differential equation was solved by adopting the deflection function compatible to the boundary condition of the pile and by transforming the deflection function to a series of linear differential equations with perturbation approach. Through exchanging the perturbation parameter of the middle deflection, the higher-order asymptotic solution of load-deflection was founded. Finally, the behavior of the pile after flexural buckling was analyzed, which shows that the pile will be unstable as the increase of the depth ratio and the stiffness ratio of the pile to soil.