Horizontal impedances of saturated soil layer with radially inhomogeneous boundary zone

The dynamic impedance of saturated soil layer with a radially inhomogeneous boundary zone to horizontally vibrating pile is theoretically investigated. A continuous, radial variation for the soil properties is assumed, so that there are no wave reflections from the fictitious interface. For the purpose of analysis, the inhomogeneous boundary zone is subdivided into a series of concentric annular sub-zones with constant material properties. The impedances of soil are obtained by adopting transfer matrix method. To verify the solution obtained herein, the computed results are compared with those obtained from earlier solution. Then, a parameter study is performed to investigate the effect of parameters involved. It is found that variations in shear modulus and the width of boundary zone have significant influence on the soil impedances.