不同土介质模型对相互作用体系地震反应的影响分析

Study on Influence of Different Soil Constitutive Models on Seismic Responses of Interaction Systems

土的动力计算模型及其参数的确定是土-结构动力相互作用分析的一个重要内容。利用有限元方法建立场地自由场和土-结构相互作用分析模型,分别采用线弹性模型、等效线性模型和Drucker-Prager理想弹塑性模拟地基土,探讨了不同强度地震动作用下Drucker-Prager模型的适用性问题,分析了不同土介质模型对土-结构相互作用体系地震反应的影响。结果表明,在场地非线性地震反应分析中,只有当输入加速度峰值在80~100 gal时,Drucker-Prager模型与等效线性模型计算结果是接近的,考虑土-结构相互作用后,两种模型计算所得的承台加速度和结构顶层加速度误差分别在8%和10%左右。因此,工程应用中应关注土介质模型的选用。

One important aspect in soil-structure interaction research is to find analysis model to simulate soil dynamics and determine parameters for this model. In this paper, Finite element method was used to build free field model and dynamic soil-structure interaction analysis model, then the foundation soil was simulated by using elastic model, equivalent linear model and Drucker-Prager model, respectively. The applicability of Drucker-Prager model subjected to different ground motion was discussed. Finally, effects for different models of soil media on seismic responses of dynamic soil-structure interaction systems were analyzed. As shown in the analysis of nonliner responses of site, the result from Drucker-Prager model would be similar with equivalent liner model as the peak acceleration is between 80 -100 gal. Considering soil-structral interaction, acceleration error of platform and structural vertex calculated from two such models are about 8% and 10%. Therefore, soil model should be paid more attention in engineering application.