Effect of tapered and semi-tapered geometry on the offshore piles driving performance

Abstract

Pile driving procedure and efficiency is not only affected by soil parameters, but also by pile geometry including the pile shape and taper angle. Several important effective factors in pile driving are hammer blow counts, penetration and velocity developed in the pile during driving. In this paper, the drivability of different pile geometries was investigated by performing field tests and numerical analyses based on finite difference method. Four steel piles have driven by hammer blows and pile driving analyser (PDA) was used to record the pile dynamic responses. The time histories of the pile head force, settlement, and velocity have been continuously monitored under each hammer blow during the driving tests. The numerical analysis with simulating the soil-pile system in the driving process has been also investigated and compared with the obtained results from the field tests. Parametric studies have been performed on effective parameters on driving such as pile geometry and embedded length. The results indicate that the pile geometry such as tapered and semi-tapered can offer better drivability performance with decreasing cumulative hammer blow counts, increasing the piles' velocity and settlement and the efficiency of the driving operation. These are remarkable in pile driving scenario.