I found the recent paper by Metrikine et.al. (most of the authors are from Delft University) entitled “GDP: A New Technology for Gentle Driving of (Mono)Piles” interesting about combining longitudinal and rotational vibrations to install piling in a “gentler” manner.
But is this new? Not really, as can be seen in this excerpt from Immersion and Extraction by Longitudinal-Rotational Oscillations:
More efficient were longitudinal and rotational oscillations, which made it possible to sink pipes at a specific pressure of 0.15 – 0.2 MPa and with a power requirement 1.6 times less than under the same conditions using longitudinal oscillations (M. G. Tseitlin, 1958). The results of these experiments showed the practicality of using multidirectional oscillations to sink hollow cylindrical elements into the ground.
Many years ago Vulcan commissioned the translation of portions of the book Vibro-Engineering and the Technology of Piling and Boring Work from whence this comes, and have had them on this site for a long time. A schematic of the process is above right.
vulcanhammer.info 
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