场地土性对核岛隔震结构影响的振动台试验研究

Shaking Table Tests of the Influence of Site Soil Properties on Isolation Structure of Nuclear Island

为研究不同地基土的土-结构动力相互作用对基础隔震体系动力反应影响规律,配备了3种不同硬度的地基土,开展土-群桩-核岛体系与土-群桩-隔震支座-核岛体系结构动力相互作用振动台试验,分析了不同场地土之间桩土相互作用、上部结构动力响应特征、桩身内力分布、变形规律以及破坏情况等。结果表明:地基土硬度的变化,对隔震体系桩-土相互作用有明显影响。随着桩土刚度比的增大,基础隔震支座的隔震效率逐渐减小,且土结分离现象更为明显;对于隔震结构,在不同场地土中加入隔震支座后,桩身受弯峰值随着土体刚度增大沿桩身高度逐渐增大;核电工程采用隔震支座时,应考虑不同场地土地基对于桩基础受力分布的改变,做出相应加固措施,以保证其安全性。

In order to study the influence of soil-structure dynamic interaction of different foundation soils on the dynamic response of base isolation system,three kinds of foundation soils with different hardness were equipped to carry out shaking table tests of dynamic interaction between soil-pile-nuclear island system and soil-pile-isolation bearing-nuclear island system.The pile-soil interaction between different sites,the dynamic response characteristics of the super-structure,the distribution of internal force of the pile,the law of deformation and the failure of the pile were analyzed.The results show that the change of foundation soil hardness has obvious influence on the pile-soil interaction of isolation system.With the increase of pile-soil stiffness ratio,the isolation efficiency of base isolation bearing decreases gradually,and the phenomenon of soil-structure separation is more obvious.For the isolated structure,after the isolated bearing is added to the site soil with different hardness,the bending peak value of the pile increases along the pile height with the increase of the soil stiffness.When the isolation bearing is used in the nuclear power engineering,the corresponding reinforcement measures should be taken to ensure its safety by considering the change of the stress distribution of the pile foundation in different soil foundation.