【摘要】 为揭示地下结构地震破坏机理,采用离心机振动台试验模拟地铁车站地震破坏过程.试验利用低强度微粒混凝土和钢丝制作了1∶50的单层双跨地铁车站模型;采用砂雨法制备了相对密实度为45%的地基模型并用硅油对其饱和;研制了适用于不同尺寸地基模型的真空饱和装置;监测了在离心加速过程中和峰值加速度分别为0.08g和0.20g的宁河波作用下地下结构及其周围土体的响应.试验结果表明:在车站结构和上覆土体自重作用下,车站立柱承受较大的轴向压力;在弱震(0.08g)作用下,结构附近土体超静孔隙水压力消散明显快于同深度其他位置土体;在强震(0.2g)作用下,3根立柱柱底发生破坏,是整个车站结构的薄弱点,车站侧墙与底板交界处出现明显裂缝.更多还原

【Abstract】 In order to reveal the mechanism of metro station damage induced by seismic load,centrifuge shaking table test was carried out to simulate the seismic damage process of subway station.Using microconcrete with low strength and steel wire,a one-story two-span metro station model(1∶50 scale) was built.This model was placed in silica sand(saturated by silicone oil) by pluviation and the relative density was 45%.A vacuum saturation equipment was designed which is suitable to varisized foundation model.The dynamic responses of underground structure and sand were monitored during the accelerated process of the centrifuge and the excited process with Ninghe waves whose maximum acceleration peak values were 0.08g and 0.20g respectively.Test results showed that during the accelerated process of the centrifuge,large axial pressure was beard by the columns of station under the weight of metro station and overlying soil.Under the excitation of 0.08g Ninghe wave,the dissipation of the excess pore water pressure near the structure was much faster than that of other places in the same depth.When the model was subjected to 0.2g Ninghe wave,the bottom parts of all the three columns,which were the weak points of metro station,were damaged and there were appreciable cracks in the junction of sidewalls and base plate.更多还原