远场长周期地震动下桩-土-层间隔震结构振动台试验研究

软土地基条件下土-结构相互作用(SSI)效应会对隔震结构的减震效果及动力特性产生影响。远场长周期地震动使隔震建筑这类长周期结构地震响应强烈，考虑SSI效应后地震响应可能更大。开展软土地基上层间隔震结构模型振动台试验研究，对比分析远场长周期和普通地震动下隔震层和隔震结构的楼层加速度和位移响应，研究远场长周期地震动下桩-土-层间隔震结构动力响应规律及减震效果。结果表明：软土地基具有明显的滤波效应，抑制高频分量，放大中低频分量；普通地震动下层间隔震结构的减震效果较显著，随着输入加速度峰值增大，减震效果降低，而远场长周期地震动下的层间隔震结构的减震效果比普通地震动下的差；基础及隔震层的转动效应明显，隔震层对基础转动有一定放大效应，远场长周期地震动下的隔震结构的放大效应较普通地震动下的明显，并对隔震层位移反应的影响较大。

Shaking table test of pile-soil inter-story isolated structure under far-field long-period ground motion

Considering soil-structure interaction (SSI) effect on soft soil foundation will affect the seismic isolation effect and dynamic characteristics of the isolated structures. The seismic response of long-period structures such as isolated buildings under the far-field long-period ground motion is strong, which may be greater after considering the SSI effect. In order to explore the mechanism of dynamic response and seismic isolation performance of the system of pile, soil and inter-story isolated structure under the far-field long-period ground motion, the shaking table test was carreid out on the model of the inter-story isolated structure on the soft soil foundation. The story acceleration and displacement response of the isolation layer and the isolated structure under the far-field long-period ground motion and ordinary ground motion were compared and analyzed. The results show that the soft soil foundation has an obvious filtering effect, which can mitigate the high-frequency component and enlarge the medium and low-frequency components. The seismic isolation effect of the inter-story isolated structure under the ordinary ground motion is more significant, and the seismic isolation effect decreases with the increase of the peak ground acceleration, while the seismic isolation effect under the far-field long-period ground motion is far worse than that under the ordinary ground motion. The foundation and the isolation layer have an obvious rotation effect, and the isolation layer has a certain amplification effect on the rotation of the foundation. The amplification effect is more obvious under the far-field long-period ground motion than that under the ordinary ground motion, which is related to the larger response of far-field long-period ground motion to the displacement of the isolation layer.