Characteristics of Negative Skin Friction for Superlong Piles under Surcharge Loading

摘要

This paper presents the study of negative skin friction of the superlong pile caused by the soil settlement under large-scale surcharge loading. Based on the displacement equilibrium principle and transfer matrix method, with the introduction of a load transfer model considering shaft resistance softening, the analytical model of negative skin friction of superlong pile under surcharge loading is established by considering the three-dimensional consolidation settlement along the pile under surcharge loading, the compression deformation of pile, and the soil settlement around pile-end. Three-dimensional Biot consolidation is used to derive the settlement of soil surrounding pile and the settlement formula is simplified by using the Laplace and Hankel integral transform. Furthermore, the analysis is conducted for an engineering example using the theoretical model and FEM simulation method. The results are also compared with the corresponding measured data. The characteristics of negative skin friction of superlong pile under surcharge loading are obtained, and the effect of soil parameters on negative skin friction is discussed as well, which can offer valuable reference for the design of superlong piles.