Finite element analysis of bored pile-frozen soil interactions in permafrost

Based on the commercially available finite element analysis program ANSYS, a finite element model of single pile-frozen soil interaction in three-dimensional system of frozen soil is established. The states of conglutination, slippage, and cracking between pile and frozen soil are simulated by the surface-surface contact. The reasonable values of contact parameter are given, and their influences on the P-S curve are analyzed. Both the experiments and the theoretical analysis are conducted to study the stresses and settlements of bored pile foundation under static axial load in the frozen soil. The results show that the bearing capacity of pile foundation in permafrost is mainly provided by the cohesion of layered frozen soils; three-dimensional high-order contact elements are able to stimulate the nonlinear boundary condition of the pile-frozen soil, and correctly reflect the stress states of the single pile in permafrost region. The finite element results are in good agreement with the experimental data. Accordingly, the validity of the model is verified.