桩底土为标准线性体模型时层状土体中桩顶振动响应

Pile vibration response in layered soil for standard linear model of subsoil

研究了桩侧土为广义Vogit体模型,桩底土为标准线性体模型,层状场地土体中桩的纵向振动特性.首先利用拉普拉斯变换并引入初始条件和边界条件,推导出位移阻抗函数.之后根据阻抗函数的传递性求得了在简谐激振力作用下桩顶频域响应解析解.最后结合具体算例,分析了考虑桩底土为标准线性体条件下,桩侧土体剪切波速的变化对桩顶速度导纳曲线的影响.研究表明:土体剪切波速的变化对对桩顶速度导纳曲线峰值影响较大,对曲线的振动频率影响很小.层状场地土体特性相差越大,桩顶速度导纳曲线峰值越大.正常沉积土层中桩顶速度导纳曲线峰值明显大于非正常沉积土层.

This paper studies vertical vibration characteristics of pile in layered soil when the pile subsoil is assumed as standard linear model and the lateral soil is assumed as Vogit model. The displacement impedance function is derived based on Laplace transform and boundary condition between pile and soil. According to the transfer function of the impedance the frequency response solution of pile top is calculated at the harmonic excitation force. Finally, a numerical example is analyzed considering pile subsoil as standard linear model. The results showed that the soil shear wave velocity has great effect on the peak of velocity admittance curve and little effect on the vibration frequency. The difference of layered soil characteristics is bigger; the peak of pile top velocity admittance curve is greater. The velocity admittance curve of pile top in normal sedimentary soil is significantly higher than that in abnormal sedimentary layer.