超大直径单桩基础高频振动贯入过程中的土塞效应

Soil plugging effect during driving of large diameter mono-pile by vibratory hammers

为了研究海上风电塔超大直径单桩基础在高频振动贯入过程中桩管内土柱与土塞效应间的关系,建立超大直径超长单桩基础高频振动贯入的欧拉—拉格朗日耦合(CEL)有限元模型,对超大直径超长单桩振动贯入两种不同类型土过程中的土塞效应进行了数值模拟研究分析。研究结果表明,超大直径超长单桩在高频振动贯入过程中很难出现土塞完全闭塞的现象,仅可能在砂土地基中出现土塞部分闭塞的现象,且作用在土塞端部的贯入阻力会向桩壁处的径向应力转移,内侧摩阻力在某一时间点后会逐步大于外侧摩阻力,内侧压力系数也随之增大。

In order to investigate the soil plugging effect during high-frequency penetration of wind turbine mono-piles, a coupled Eulerian-Lagrange model for the vibratory penetration of the monopiles was established,and the soil plugging effect during the vibratory penetration of the large diameter monopiles into different soils was simulated and studied. According to numerical simulation results,soil is unlikely to be completely plugged during the penetration of the large diameter monopiles,while sand may be partially plugged in the vibratory penetration of mono-piles. When a monopile is vibrantly driven into sand,the penetration resistance at the pile end will be transferred to the radial stress around the pile wall,the internal shaft friction will become larger than that of the external shaft friction,and the radial pressure factors will increase when the sand is partially plugged.