基于弹塑性模型的群桩-土-结构动力非线性数值分析

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。

Nonlinear dynamic time history analysis of pile-groups-soil-structure based on elsto-plastic model

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 seismic 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 structure.By using the simplified method,the designers can carry out dynamic time history analysis and seismic evaluation for the superstructure quickly,accurately and efficiently.