斜桩锤击过程中桩顶力学响应研究

Mechanical response of pile top during hammering inclined pile

针对上海某港池工程12°斜桩桩头断裂的动力响应问题,对斜桩每节桩的桩头进行现场应变监测,利用ABAQUS软件对直桩、6°和12°斜桩进行有限元模拟,对比桩锤质量、桩距进行优化前后的桩顶动力学响应,并得出锤击频率、锤击速度对桩顶应变的影响。结果表明,同等锤击荷载作用下,桩的拉、压应变随桩身倾角的增加而增加,12°倾角产生的拉、压应变峰值最大;增大桩锤质量、降低桩锤与桩顶距离,可降低桩顶应变;桩头应变监测值与模拟值的变化趋势一致;有限元模拟把桩锤的冲击力等效成三角荷载的方法是合理的。

Aiming at the problem of dynamic response to the fracture of 12°inclined pile heads at a harbor project in Shanghai,we carry out the strain monitoring of pile head of inclined pile at the site,perform finite element simulation of straight pile,6°and 12°inclined pile by ABAQUS software,compare the dynamic response of pile top before and after optimization of the pile hammer mass and falling distance,and obtain the influence of hammering frequency and hammering speed on the strain of pile top.The results show that under the same hammering load,with the increase of the inclination of the pile body,the tensile strain and compressive strain of the pile also increase,and the peak value of the tensile and compressive strain produced by the 12°inclination angle is the largest;increasing the mass of the pile hammer and reducing the falling distance to the pile top can reduce the strain at the pile top.The monitoring trend of the pile head strain is consistent with the change trend of the simulated value.The method of equating the impact force of the pile hammer with the triangular load by finite element simulation is reasonable.