大比例模型稳态激振试验研究

Test Research on the Steady State Excitation Large-Scale Model

设计并制作了一个土桩上部结构动力相互作用1/2比例框架模型,并对模型进行了弹性范围内的顶部稳态激振试验.对比了忽略重力加速度模拟模型、部分考虑重力加速度模拟模型、考虑重力加速度模拟模型3种工况下顶部机械激振的模型动力反应情况,发现结构顶部速度响应与底部速度响应存在较大不同,并且随着所考虑的重力荷载的增加,模型的基频逐渐降低,频率的变化基本符合相似规律.通过与实测值进行对比发现,本文所建有限元计算模型基本符合实际情况.通过计算,发现结构的频率、加速度响应随土层弹性模量的变化基本呈指数函数变化,提出了通过制造基于考虑土结构动力相互作用的人工地基达到减震效果的新思路.

A 1/2-scale frame model of dynamic soil-pile-structure interaction was designed and manufac- tured, and the tests of its steady state excitation in elastic range were carried out. The dynamic responses of steady state excitation tests under three circumstances, namely, when the gravity simulation model was not considered, was partly considered and was totally considered, were compared. It was found that the velocity responses were different at the top and at the bottom. The fundamental frequency of the model decreased and the change of the frequency accorded with the similarity ratio with the increase of gravity load. After a comparison of the measured value, the computational model of this paper was in agreement with the facts. By analyzing the computational model, the change of frequency and the acceleration were distributed exponentially with the change of the soil elastic modulus, and the artificial foundation based on soil-pile-structure interaction could achieve damping effect.