Comparison between ground vibrations induced by impact piling and bored piling.

During piling activities, vibration is generated from the pile driver to the pile then it transferred at the pile-soil interface. However, the level of ground vibration induced by piling may depend on several factors including energy and distance from the vibration source. The objective of this study is to investigate characteristics of ground vibration that propagate during piling to be done by two different types: bored pilling and impact pilling. Change in characteristics of ground vibration with the distance from the pile driver was also investigated. Two bored piling sites and an impacted piling site were selected for this study. In the selected piling sites, ground vibrations were measured at 5m, 10m, 15m and 25m distances from the source in three radial directions by using a four channel seismograph. It was found that, for both types of pilling, magnitude of the vibration reduces with the distance. Impact piling induces high magnitude and low frequency vibration whereas bored piling induces low magnitude and high frequency vibration. In transverse direction, impact piling induces a magnitude of 4.21mm/s (PPV) at a frequency of 20Hz, whereas bored piling induces a magnitude of 0.92 mm/s (PPV) at a frequency of 36.5 Hz, at 5m distance from the source. Characteristics similar to the transverse vibration were found in both vertical andlongitudinal vibratio ns