软土地层十字换乘站振动台单向地震试验研究

Research on Shaking Table Single Direction Seismic Test of Cross Interchange Station in Soft Soil

设计并开展软土地层十字换乘站单向地震大比尺振动台试验:从动力平衡方程出发,提出了基于人工配置模型土的相似设计方法;以土-结构相对刚度比为控制指标,提出采用微粒混凝土和镀锌钢丝模拟车站结构。基于振动台试验,研究了软土地层中二层与中三层的十字型换乘站的结构地震响应特性,并以单体车站为参照试验,揭示了软土地层十字型换乘站结构单向地震响应特征。结果表明:随着地震动增强,土体剪切模量衰减程度增加;受换乘站结构的差异约束作用,近场土体加速度响应存在空间差异现象,幅值整体小于自由场;换乘站交叉节点处地下三层中柱应变显著高于地下一、二层,在抗震设计中应引起重视。

Large-scale shaking table single direction seismic test of cross interchange station in soft soil is designed and conducted.From dynamic balance equation,a similar design method based on synthetic model soil is proposed.The model station structure adopts granular concrete and galvanized steel wire,taking soil-structure relative stiffness as control index.Based on shaking table test,the structure seismic response characteristics of two-storey and three-storey cross-type interchange station in soft soil is studied,and parallel tests of single station are carried out for reference.Test results show that with ground motion enhances,the soil shear modulus attenuation grade increases.Due to the differential restrained effects of the interchange station structure,near-field soil acceleration experience spatially different phenomenon,and the amplitude is overall smaller than in the free-field.The bending strains of 3 rd level underground middle column at interchange station cross joint is significantly higher than that of the first and second level underground,raising concern for future seismic design.