非完整桩瞬态纵向振动的模拟计算

根据完整桩瞬态激振力作用下纵向振动的模型,建立了非完整桩的纵向振动的动力学模型,给出桩身运动方程、桩顶与桩底的边界条件及初始条件,并用有限差分法解出桩身各点在不同时刻的速度值。用桩顶振动速度时程图非常直观地研究了桩中应力波的传播过程,同时,考虑了桩半径、桩长、动测波速、激振力的冲量及其作用时间、桩底土的参数变化、桩周土的参数变化等情况。将理论计算的波形图和工程桩动测波形图进行比较,显示出很好的一致性。

Simulation and calculation of transient longitudinal vibration of non-integrate piles

Based on the model of integrate piles under the action of transient vibration force,the transient longitudinal vibration model of non-integrate piles is established. From the movement equation of a pile and the boundary conditions and the initial conditions at the top and bottom of the pile,the velocity of the certain position on the pile at certain time can be computed by the finite difference method. The velocity-time graph of the pile top directly shows the transmission process of the reflected wave in the pile. In the computation,the variation of different parameters such as the radius and length of the pile is also investigated. The theoretical response correlates well with the dynamic testing of an engineering pile by the reflected wave method.