土–桩–隔震结构动力相互作用体系振动反应特性试验研究

Experimental study on vibration characteristics of soil-pile-isolated structure dynamic interaction system

软夹层地基条件必将会对隔震结构的隔震效率及其动力反应特性产生一定的影响。鉴于此,基于软夹层地基上基础隔震结构地震反应的振动台模型试验结果,对比分析了不同频谱特性和不同强度地震动作用下软夹层地基、基础隔震层和隔震结构的振动加速度反应特征,初步给出了软夹层地基上土–桩–隔震结构动力相互作用体系的振动反应特性及其规律。结果表明,试验设置的模型地基基本上能够反映软夹层地基的地震反应特性。同时,输入地震动频谱特性及其强度对软夹层地基上基础隔震层的隔震效率及其隔震结构的动力反应规律都具有明显的影响,造成上述影响的主要原因应为软夹层地基明显改变了输入地震动的频谱特性和强度,起到了天然隔震的作用,其具体影响规律和影响程度还需做进一步的深入研究。

Isolation efficiency and dynamic response of base-isolated structure are certainly influenced by the soft interlayer foundation conditions. Based on the model shaking table tests, the earthquake response characteristics of the soft interlayer foundation, base-isolation system and isolation structure under different spectral characteristics and intensities of input ground motion are analyzed and compared. The earthquake response characteristics and rules for the soil-isolated structure dynamic interaction system are obtained. The results show that the model foundation can reflect the earthquake response characteristics of soft interlayer foundation. At the same time, the spectral characteristics and intensities of input motion have significant impacts on the efficiency of isolation layer and the change law along the vibration response of base-isolated structure. The main reason is that the characteristics of the input motion are changed obviously by the soft foundation, which plays the role of a natural isolation layer for the upper structure.