Experimental study on penetration characteristics of an open-ended pile under static and dynamic driving methods

Open-ended piles have been widely adopted in both offshore and onshore geotechnical engineering projects. However, the influence mechanism of pile driving methods on the penetration characteristics of the open-ended piles is not clear. Therefore, this paper presents simulations of an open-ended pile penetrating through a silt layer to a fine sand bearing stratum using static and dynamic driving methods respectively in a series of indoor model tests. Properties including pile sinking resistance, pile end resistance, pile side friction resistance, pile load transfer law and soil plug formation during penetration are analyzed. The results show that the PLR value of the hammered pile is always greater than that of the static pressure pile in the stable sinking stage, while the IFR value of the latter in the sand layer is significantly higher than that of the former. The resistance of the hammered pile under the same penetration depth is less than that of the static pressure pile and increases sharply when entering the holding layer. In addition, the final pile driving resistance of the hammering method is 66.68% of the static pressure pile driving resistance, and the pile end resistance from the static pressure method and hammering method account for 75.4% and 77.6% of the total resistance respectively In the choice of construction method, the static pressure method is more suitable for silty soil, and the hammering method can show its advantages in fine sand formation.