Dynamic behaviour of pile foundations in layered soil medium using cone frustums

An analytical method using a cone model is developed to evaluate the impedance functions of pile foundations in a layered soil medium. The dynamic behaviour of piles depends on the nature of the interaction between the piles and the surrounding soil. The soil–pile interaction effect modifies the stiffness of the piles and generates damping through energy radiation to infinity. This modified complex stiffness is called the impedance function. A physical model called a cone frustum is developed to represent the layered soil medium. It is capable of incorporating the complexity of layered soil media and the complicated behaviour of propagating waves. The analytical tool is developed based on wave propagation principles.