大比例模型结构-桩-土动力相互作用试验研究与理论分析

TEST INVESTIGATION AND THEORETICAL ANALYSIS OF LARGE-SCALE MODEL ON DYNAMIC SOIL-PILE–STRUCTURE INTERACTION

介绍了一个土-桩-框架结构1/2比例模型动力相互作用野外试验研究,通过对模型进行地脉动测试得到了其基频,并分别在忽略重力、欠人工质量、人工质量三种工况下进行了模型的顶部牵引激励试验和顶部机械激励试验,且在时域和频域内分析了试验结果,得到了一些有益结果。此外,研究了考虑土体动力非线性特征的粘弹性人工边界,提出了考虑桩土动力相互作用中桩土分离、滑移以及基础提离效应的接触模型,并引入阻尼项表征桩土动力作用中的能量损耗。建立了试验模型结构的三维有限元分析模型,通过对模型试验的模拟计算验证了有限元模型的可靠性,进而进行了不同地震动输入下的地震反应分析,总结了一些规律性结果。

A 1:2 model of dynamic soil-pile-superstructure interaction was built and its interactions between the soil and the pile and the superstructure were investigated on the outside site. Its nature frequency was obtained through ground micro-tremor test, and model test of top draw-releasing vibration and top machine induced vibration were executed under the condition of no gravitational force, insufficient-artificial mass and artificial mass, and some valuable results have been obtained by analyzing of the test data in time domain and frequency domain. Furthermore, after taking into account the dynamic nonlinear behaviors of soil, a viscous-spring artificial boundary has been studied, and a new three-dimension contact model of soil-pile dynamic interaction is presented, which considers the effect of separating, sliding and base uplifting in dynamic soil-structure interaction, as well as the energy dissipation during the dynamic interaction. The three-dimension finite element model has also been established, and the model tests were simulated. The finite-element-model computing results satisfy the tests’ results. Some regularity of soil-pile-structure interaction was obtained from earthquake response under groundmotions of different frequency spectrum features.