水平地震下土-桩-结构相互作用简化分析方法

基于 Penzien 提出的集中质量法,将上部结构和桩基离散为剪切型质点串,以弹簧和阻尼器模拟周围土体,建立土-桩-结构动力相互作用的分析模型,给出相互作用参数的确定方法,并考虑土体的动力非线性和材料阻尼特性,通过等价线性迭代逼近土体的非线性动态响应.运用此模型对某180m 混凝土烟囱按桩基础和刚性基础两种方案进行自振特性和地震时程反应对比分析,得到两种基础形式结构的位移、剪力、弯矩的分布形式基本一致,但考虑桩-土-上部结构相互作用的桩基础使结构体系的周期延长,变形增大,剪力和弯矩相应减小.桩-土-上部结构相互作用增加了结构的柔性,改善了结构的抗震性能.

Simplified analysis of soil-pile-structure dynamic interaction under lateral seismic loading

Based on lumped masses model developed by Penzien,the soil-pile-structure dynamic interaction analysis model was constructed with a set of bend-shear lumped masses representing the structure,pile group, and springs,dashpots which represent surrounding soil.Calculations were made for interaction parameters with the nonlinearity and damping characteristic of soil taken into consideration.Approximation of equivalent linear iteration was employed to obtain the solution to the governing equation.Free vibration and seismic response analysis in time domain and comparitive analyses were conducted for a 180-metre chimney with two different foundation type,rigidity and pile group foundation,using above mentioned model.Some useful conclusions were put forward finally for reference to seismic design.