砂–细粒混合料场地地震反应特性

Seismic Response Characteristics of Sand-fine Mixture Field

砂–细粒混合料动力学性质特殊,关于砂–细粒混合料场地地震反应特性的研究却鲜有报道。为了探究砂–细粒混合料场地地震反应特性,结合共振柱试验数据,利用有限元软件,讨论了混合料土层厚度、细粒含量及类型等因素对砂–细粒混合料场地地震反应特性的影响。结果表明:随着细粒含量的增大,不同混合料场地的基本周期呈现出先增大后减小的趋势;混合料场地地表峰值加速度放大倍数基本呈现出先下降,后波动,最后稳定的非线性变化趋势。细粒含量与类型对混合料场地反应谱比的影响与周期有关。造成混合料场地地震反应非线性变化的原因,主要是由于随着细粒含量的增加,混合料土体由类粗粒土向类细粒土转变而导致的。随着混合料土层厚度的增大,该非线性变化更加显著。

The dynamic properties of sand-fine mixture are unique.However,the study about seismic response characteristics of sand-fines mixture field is seldom reported.In order to explore the seismic response characteristics of sand fine mixture field,combined with resonance column test data,the influence factors of mixture layer thickness,fine content and type on seismic response characteristics of sand-fine mixture flied are discussed by using finite element software.The results show that:with the increase of fine content,the basic period of different mixture sites first increases and then decreases;the amplification ratio of peak ground acceleration of mixture sites basically shows a nonlinear trend of first decreasing,then fluctuating,and finally stable.The influence of fine content and type on the site response spectrum ratio of mixture is related to the period.The non-linear change of seismic response of mixture field is mainly caused by the change from coarse-grained soil to fine-grained soil with the increase of fine content.The nonlinear change is more significant with the increase of mixture layer thickness.