【摘要】 设计并完成两项刚性桩复合地基-结构系统1∶10比尺的振动台模型试验,对在类似地基-结构系统的普通振动台模型试验中如何使模型与原型相似的几个突出问题进行研究,包括:地基模型箱的选用,以较好模拟地基在地震作用下的振动变形;在重力场相似难以满足的情况下,降低其影响的措施;解决模型结构阻尼比偏低问题的方法。试验中采用柔性地基模型箱,在基础底板用拉索施加下拉力使基底压力在重力场失真情况下基本满足相似条件,在结构模型上附加层间阻尼器使其阻尼比接近实际。通过对试验结果的对比分析,研究上述措施的效果。结果表明,柔性容器可以较好地模拟地基土体在地震下的变形;在基础底板施加竖向力以使基底压力相似的方法有较好的效果;而层间阻尼器可以有效调整模型结构的阻尼比而无其他较明显的不利影响。更多还原

【Abstract】 Two shaking table tests,with a scaling factor of 1/10,for the seismic response of rigid pile composite foundation-structure systems were carried out to investigate the similitude realization issues,which include the design of the soil container to better simulate the shaking deformation of the soil,the measure to reduce the influence of non-similarity of the gravity field,and the adjustment of the damping ratio of the model structure to make it close to reality.Flexible container was employed.Pulling cables were used to apply downward force on the foundation to make the pressure underneath satisfy the similitude condition,and dampers were mounted on the structure model to adjust its damping ratio.Effects of the above measures were carefully examined by comparative analyses of the test results.It is proved that the flexible container could adequately simulate free field boundary conditions in the soil,that the approach to simulating the pressure underneath the foundation was satisfactory,and that the dampers mounted to the model structure could simulate the damping property of actual building structures effectively without any significant side effect.更多还原