基于桩周土纵向非均质性的桩顶阻抗函数研究

Impedance of a pile considering vertical heterogeneity of surrounding soil

为研究桩周土纵向非均质性对桩顶阻抗的影响,以平面应变模型来模拟桩周土,采用Rayleigh-Love杆模型来考虑桩身的横向惯性效应.将桩土系统划分为数量足够多的微元层,结合阻抗函数递推法,求得在考虑桩周土纵向非均质性情况下桩顶的阻抗函数.本文解可以退化到经典解,这也验证了文中所得解的合理性.通过参数分析研究了桩顶的动刚度和动阻尼随桩周土竖向非均质程度变化的规律;在考量桩周土的纵向非均质性后,桩顶的动刚度和动阻尼都有一定程度的增大.

The effects of the vertical heterogeneity of the surrounding soil on the impedance function at the pile top are investigated. The surrounding soil is modeled using plain strain model. The Rayleigh-Love rod is introduced to consider the transverse inertial effect. The pile-soil system is divided into layers of sufficiently large number. Then the impedance function at the pile top can be derived using impedance function transfer method. The proposed solution can be degraded to classical solution, with which its validity can be confirmed. The dynamic stiffness and damping at the pile top are studied through parametric analysis. It is found out that when vertical heterogeneity of the surrounding soil is taken into consideration, the dynamic stiffness and damping at the pile top shall demonstrate certain increase.