Dynamic soil resistance to vertical vibration of pipe pile

Abstract

Pile-soil interaction affects the pile dynamic characteristics and its response to dynamic loads. The one-dimensional rod model widely used to analyze the response of pipe pile is inaccurate, especially for large-diameter pipe piles. An axisymmetric pipe pile-soil interaction model is proposed to account for vertical and radial displacements of both the pile and soil medium. Analytical solutions are deduced for vertical vibration of open-end and closed-end pipe piles under harmonic excitation. Based on the obtained solutions, soil resistance factor (SRF) is defined to evaluate the dynamic soil resistance along the pile shaft. The model is verified by comparing its predictions with those obtained from existing solutions. The verified model is then used to conduct an extensive parametric study to evaluate the influence of different parameters on the dynamic soil resistance of the pipe pile supported by inner and outer soils. The results show that the inner SRF is much smaller compared to outer SRF. It is also found that stiffness factors of SRFs of inner and outer soils are almost independent of each other. However, the damping of inner SRF is greatly influenced by properties of the outer soil.