结构─地基相互作用体系的动力相似关系研究

Study on dynamic similitude theory of soil-structure interaction system

模型试验的动力相似理论是结构试验技术中的一个重要的基础性研究课题。本文设计实现了缩比为１／２０和１／１０的结构─地基相互作用体系的振动台模型试验，通过对两个模型的试验结果的对比研究，对结构─地基相互作用体系的动力相似关系进行了初步探讨。按照本文的动力模型的设计施工及试验原则进行的模型体系的振动台试验，在结构─地基动力相互作用体系的主要特征和规律方面有较好的相似性。在激励较小阶段和激励较大阶段，两个缩尺模型在动力特性、加速度反应时程以及上部结构的应变反应等方面具有较好的相似关系；但在试验的中间阶段，两者存在明显的差异，影响两个缩尺模型在试验中间阶段的相似性的主要原因是上体在模拟地震激励下的非线性发展程度的差异。

Dynamic similitude theory of the model tests is a basic research topic in structure test tech- nique. Shaking table model tests of two soil-structure interaction systems with the scale factors of 1/20 and 1/10 respectively are designed and implemented in this paper. By comparing the results of these two model tests, dynamic similitude relations of the soil-structure interaction systems are dis- cussed preliminarily. The similitude properties of the two test models are good when the design, construction and arrangement of shaking table model tests are done as in this paper. When excitation is either very small or very large, the two models with different scale factors have quite good similitude relations in dynamic property, time history of acceleration response and strain re- sponse of the superstructure. However, there is certain difference when excitation is moderate. The main reason for this phenomenon is the difference of developing degree of the soil nonlinear behav- ior under moderate excitations.