Impedance Functions of Piles in Layered Media

An approximate analytical solution is established that makes it possible to calculate impedance functions (stiffness and damping) of a single pile embedded in layered media. The pile can be of stepwise variable cross section and feature any tip condition. The impedance functions are complex and frequency dependent but can be obtained by means of a computer program that is simple and very inexpensive to run. A comparison of the theory with experiments indicates the potential of the theory and demonstrates the need to consider the variation of soil properties with depth and lack of the fixity of the tip for short piles.