振动锤沉桩计算方法

Calculation method of pile drivability by vibratory hammer

振动沉桩过程中由于桩周动摩阻力的影响,桩身振动加速度随着入土深度的增加而逐渐减小,动摩阻力随着入土深度的增加而逐渐增大,当振动锤激振力能够克服桩侧动摩阻力及端阻力,同时桩端产生的最大振幅能够克服土处于弹性阶段的最大位移后桩可继续下沉。通过对桩身划分单元的方法,确定桩侧动摩阻力与桩身振动加速度之间的关系,计算得到不同入土深度位置的桩侧振动加速度,同时考虑应力波在桩身的传递,最终获得桩在不同时刻的动摩阻力,并通过桩端单元的振动加速度计算得到桩端最大振幅。

While the pile was subsiding, because of the effect of dynamic friction around piles, the vibratory acceleration of the pile body was decreased along the depth into soil, and the dynamic friction was increased along the depth into soil. When the vibratory hammer exciting force is greater than the sum of dynamic friction and the pile end resistance, and if the max amph- tude at the bottom of the pile is greater than the elastic deformation of the soil, the pile could submerge continuously. Through the method for dividing the pile into unit, we determined the relationship between the friction and acceleration of the pile, calcu- lated the accelerations of different unit, considered the stress wave passed in piles and then got the dynamic friction of the pile in different time. The max amplitude at the end of the pile could be obtained by calculating the vibration acceleration of the unit.