扭转波应用于低应变动力测桩的理论研究

给出层状土中多缺陷桩在桩顶冲击扭矩作用下桩顶扭转响应的解。考虑了桩土相互作用。应用Laplace变换和传递矩阵 ,解桩的满足初始条件和边界条件的一组偏微分方程 ,导出桩土系统的传递函数 ,得到桩顶某点扭转振动速度的频率响应函数和频率域表达式。该点扭转振动速度时程由快速Fourier逆变换计算。用这种解研究桩的扭转波特征 ,其结论对应用扭转波进行低应变动力测桩有指导意义

Theoretical study on torsional wave applied in low strain dynamic testing of piles

A solution to the torsional response of a multi defective pile in layered soil is presented,when subjected to an impact torque at pile top.Soil pile interaction is considered in this approach. The partial differential equations of torsional vibration of pile have been solved using Laplace transform and transfer matrix,which satisfy the initial conditions and boundary conditions.The transfer function of soil pile system is derived.The frequency response function and frequency domain expression of torsional vibration velocity at a point on pile top are obtained.The time history of the velocity is calculated using inverse fast Fourier transform.The solution is used to study torsional wave characteristics of the pile.The conclusion will be of guide significance on low strain dynamic testing of pile with torsional wave.