梁-桩-土竖向耦合振动特性分析

针对桩与连续梁组合这一基础形式,研究了梁-桩-土竖向耦合振动特性. 首先,将桩假设为一维黏弹性杆件,采用平面应变模型模拟桩侧成层土对桩的动力作用. 同时,桩顶对梁的支撑简化为竖向点支撑. 然后,分别根据一维杆件纵向振动理论和Timoshenko梁理论给出桩和梁的竖向振动控制方程并求解,进而借助离散傅里叶逆变换获得在梁上瞬时激振下梁和土层以上桩段的时域响应半解析解. 通过与有限元模拟结果对比,验证了解的合理性. 在此基础上,讨论了梁几何参数和桩身缺陷对梁-桩-土竖向耦合振动特性的影响.

VERTICAL COUPLING VIBRATION OF BEAM-PILE-SOIL SYSTEM

The vertical coupling vibration of beam-pile-soil system is investigated. First, the piles are assumed to be viscoelastic rods, and the plane strain model is employed to simulate the dynamic interactions between piles and surrounding soil layers. The dynamic beam-pile interactions are simplified as vertical point loads. On this basis, the matrix equation for solving the governing equations of motions for beam and piles is constructed in the frequency domain. The quasi-analytical solution in the time domain is then obtained by the discrete inverse Fourier transform. A comparison with numerical simulation is conducted to verify the rationality of the present solution. Finally, the effects of the geometric parameters of beam and pile defect on the dynamic response of beam-pile-soil system are discussed.