三维波动土中考虑桩身变截面与桩周土相互作用的大直径桩的动力特性

采用Voigt体来模拟桩身变截面与土的相互作用,得到了三维波动土中考虑变截面与土相互作用的大直径桩–土作用模型。对桩身变截面处的应力平衡和应变连续条件进行拉普拉斯变换,得到修正的阻抗函数递推法。桩周土采用考虑径向和纵向波动的三维轴对称模型,桩身采用黏弹性Rayleigh-Love杆来考虑大直径桩的横向惯性效应。结合修正的阻抗函数递推法,通过求解桩土动力平衡方程得到了桩顶的速度频响的解析解和瞬态激振下速度时域响应的半解析解。通过参数分析,将所得解与忽略桩身变截面与土相互作用的解进行对比,并分析有关参数与变截面与土相互作用的耦合作用。

Dynamic response of a large diameter pile considering the interaction of variable pile section with surrounding layered three-dimensional soil

The interaction between the surrounding soil and pile with variable cross-section is represented by a Voigt model and the spring constant and damper coefficient is derived. Thus a more rigid pile-soil interaction model considering the interaction of variable pile section and surrounding soil is proposed. An amended impedance function transfer method is proposed by taking Laplace transforms on the continuity conditions of displacement and stress. The surrounding soil layers are modeled as a three-dimensional axisymmetric continuum and the pile is assumed to be a Rayleigh-Love rod with material damping to study the transverse inertial effect of the pile of large diameter. The impedance function at pile top is derived with the amended impedance function transfer method proposed in this paper. Then the velocity response at pile top is obtained. The solutions with and without the interaction of variable pile section with surrounding soil are compared. Meanwhile the coupling between the related parameters and the interaction of variable pile section with surrounding soil are analyzed.