There are generally three main vibration mechanisms caused by driving
sheetpiles:
(a) When the sheetpiles are impacted by a hammer, a compressive wave would be formed and it travels down to the toe of sheetpiles. A large amount of energy would be used to cause downward movement of sheetpiles while some of the energy would be reflected back up to the sheetpiles. The remaining energy would be transmitted to soils which expand outward as a spherical wavefront called “P” waves.
(b) The impact action of hammer causes temporary lateral deformation of sheetpiles. A surface wave is then established which travels outward from pile shaft circumferentially.
(c) The downward motion of sheetpiles arising from hammering action induces vertically polarized shear waves which propagate outward in cylindrical wavefront.
This question is taken from book named – A Self Learning Manual – Mastering Different Fields of Civil Engineering Works (VC-Q-A-Method) by Vincent T. H. CHU.
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