双向水平地震作用下场地土三维非线性反应分析

Nonlinear ThreeDimensional Seismic Ground Response Analysis in Bidirectional Horizontal Earthquake

摘要:

针对双向水平地震作用下场地土地震三维非线性反应问题，基于多重屈服面模型建立了三维竖向土柱模型，重点考察了影响场地土地震非线性分析准确性和效率的相关因素，其中多重屈服面模型参数、土层厚度划分、边界条件以及组成阻尼的频率或模态等的合理选择是进行非线性地震反应分析的关键参数.当土层性质差异明显时，可以根据波速的不同分为多个子系统，各个子系统分别选用相对应的阻尼参数进行分析.为确定分析方法的计算精度，与已有文献的离心动力试验结果对比，验证了三维竖向土柱模型的可靠性，该模型可以有效地应用于双向非线性地震反应分析.

关键词:地震反应; 多重屈服面; 双向地震动输入; 三维非线性; OpenSees平台

Abstract:

The threedimensional vertical column system and the multiyield surface plasticity constitutive model were implemented for the problem of nonlinear seismic site response to bidirectional horizontal earthquake loading. The practical issue concerned the specification of the accuracy and efficiency of site response analysis. The crucial parameters describing the multiyield surfaces, soil thickness division and boundary conditions, and frequencies or modes for the damping formulation could help preforming the accurate nonlinear seismic ground response in the bidirectional earthquake. The layered soil column was divided into multiple subsoils with different viscous damping matrixes according to the shear velocities as the soil properties were significantly different. The accuracy of the threedimensional soil column method was verified by the dynamic centrifuge model test results. It is concluded that the threedimensional vertical column model can be used for bidirectional nonlinear seismic local ground response analysis.

Key words:seismic ground response; multiyield surface plasticity; bidirectional earthquake loading; three dimensional nonlinearity; OpenSees platform