Three-dimensional wave propagation in a solid pile during torsional low strain integrity test

The torsional low strain integrity test (TLSIT) is now regarded as the most potent alternative to the longitudinal wave test for the existing pile evaluation. However, the lack of the 3D wave theory for the TLSITs greatly hinders the application of this method. This paper establishes a coupled 3D soil-pile model based on the continuum theory. A corresponding analytical solution of the dynamic pile response is derived and subsequently verified through the comparisons against the 1D wave theory and the Finite Difference Method. The proposed model exhibits the transverse wave interferences and finds: (1) The transverse wave interference that occurred during the TLSITs can be seen gradually alleviated from the pile center to the pile edge. (2) The larger the pile dimensions are, the greater the transverse wave interference would be.