群桩基础水平动力响应简化边界元频域解答

Simplified boundary element method for lateral vibration response of pile groups in frequency domain

在水平振动或地震作用下,建立圆形桩与土的动力相互作用简化边界元模型,采用动力相互作用因子对群桩基础顶部的惯性响应和运动响应进行分析。桩身运动方程考虑了群桩动力相互作用以及由土体位移引起的被动桩效应,得到了频域内固定群桩基础顶部的水平动力响应的弹性解答。结果表明,简化边界元模型通过土体位移系数,考虑了沿桩身长度方向的土体相互作用,较为准确地得到了桩身运动弯矩,将其运用到群桩基础的计算中,可以用于评估动力作用下群桩基础的桩顶水平阻抗和桩土运动响应。

A simple boundary element approach for the system of circular piles and soils is formulated to predict the lateral impedance and kinematic seismic responses of fixed-head pile groups during the lateral vibration or seismic excitation. The dynamic interaction of piles in a group and the passive pile effect are considered in the dynamic equilibrium of a pile foundation. The elastic solution to the lateral impedance and kinematic seismic responses of the massless pile cap, restricting against rotation, is obtained in the frequency domain. The results show that the soil-displacement-influence coefficient can be used to consider the pile-soil interaction along a pile and to capture the kinematic bending moment accurately. Meanwhile, the coefficients provide reasonable estimations of the lateral impedance and kinematic seismic response of pile groups.