Three-dimensional propagation of waves in piles during low-strain integrity tests

In this note the concept of discretising the pile into virtual parts is introduced in order to derive an analytical solution that describes three-dimensional propagation of waves in piles during low-strain integrity tests, considering both vertical and radial pile displacements. The effect of transverse wave propagation on the results is quantified by comparing the proposed solution against a previously published method in which only vertical displacement was considered, results of dynamic numerical analyses, as well as the classical one-dimensional solution. Using the obtained waveforms, an attempt is made to identify and describe the mechanisms of three-dimensional propagation of longitudinal waves in piles, and how these may affect the interpretation of low-strain integrity tests.