Back analysis of laterally loaded pile behavior using Midas/GTS to determine stiffness modulus of pile-soil interface

Abstract

In finite element modelling of laterally loaded pile or pile subjected to soil movement, normal stiffness (Kn) of pile-soil interface is required. However, the correlation of normal stiffness to soil stiffness is not widely available. This paper shows the results of the investigation of the normal stiffness by simulating the renowned laterally loaded pile test in Houston (in clay medium) and Arkansas (in sand medium). Series of parametric studies using 3D finite element program were carried by varying the ratio of normal stiffness to soil Young's modulus at reference level. By matching pile lateral deflection and bending moment of the pile. This study suggested that a ratio of Kn/Eoed 10 ~ 100 is acceptable for pile in clay domain while a ratio of Kn/Eoed 1 ~ 10 is acceptable for pile in sand domain. The study also found that Mohr Coulomb model fails to model the response of laterally loaded pile. By using an appropriate normal stiffness, the ultimate lateral load of the pile can be predicted by using 3D finite element program.