基于弹塑性模型的群桩-土-结构动力非线性数值分析

摘要

A pile-soil elato-platic model is provided.Combined with dynamic Winkler model,the spring-dashpot dynamic impedance related to pile (raft)-soil attributes and the frequency of SSI system is derived.A simplified three dimensional interaction finite element analysis model of soil-frame structure is established and nonlinear dynamic time history analysis is performed for this model under different seis-mic excitation and different conditions of pile-soil.The result shows that under certain ground motion and soil-foundation conditions,nonlinear effect of the upper structure can be greater than fixed base assumption and pile-group-soil soft support model also influences the weak layer position on upper struc-ture.By using the simplified method,the designers can carry out dynamic time history analysis and seis-mic evaluation for the superstructure quickly,accurately and efficiently.%提出一种群桩-土弹塑性模型，结合动力文克尔理论，推导出了与桩(筏)-土属性及 SSI体系频率相关的各项弹簧-阻尼单元动力阻抗，建立了三维框架土-结构相互作用有限元简化分析模型。针对不同地震激励，在不同桩-土条件下对模型进行了动力非线性时程分析，结果表明，在某些地震动和土-基础条件下，上部结构非线性作用效应结果可能大于固基假定情形，且桩-土弹塑性模型对上部结构柔弱层位置产生影响。应用本文简化方法可以快速、较准确有效地进行复杂的上下部结构动力时程分析及抗震评估。