横向撞击对竖直桩影响的动力分析

针对桩基础施工中使用机械清理桩头时经常遇到的撞击问题,把桩周土当作Winkler地基,运用弹塑性碰撞理论,由拉氏正变换和逆变换解析得到了桩顶受到横向冲击荷载时桩的瞬态横向动力响应;通过变换不同的桩土参数,对有限长桩和无限长桩的最大无量纲响应沿深度的变化曲线进行了分析比较.结合相应的工程实例,对竖直桩的配筋及所能承受的横向撞击速度的临界值(0.22 m/s)作了探讨,并提出了相应的施工改进措施,如控制撞击速度或调整桩身配筋等.

Dynamic Response Analysis for the Influence of Transverse Impact on Vertical Pile

According to the impact problem usually happened when the pile head is disposed by machine in the construction of pile foundation projects,the soil is treated around the pile with the application of Winkler foundation and the elastic and plastic impact theory to make the analytical solution for transient lateral dynamic response of pile subjected lateral impulse load at the pile head from direct and inverse Laplace transforms.For various range of main parameters,the parametric studies are conducted on the dimensionless maximum response along the depth to compare the dynamic behavior of a finite-long pile with that of an infinite-long one.By a correspondent project example,the distribution steel of the vertical pile and the critical speed(0.22 m/s) of transverse impact which can be endured by vertical piles are discussed and improvement measures on the construction are provided,for example,control the speed of transverse impact according with the distributed steel of vertical pile or in reverse.