冻土-结构相互作用体系振动台试验及数值分析
Shaking table tests and numerical analysis of frozen soil-structure interaction system
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摘要: 基于冻土-结构动力相互作用体系的振动台试验,利用自行研制的室内冻土冻结系统,再现了地震激励下,冻土场地中上部结构和地基的震害现象以及砂质粉土的液化现象。研究地震作用下,不同冻结深度的冻土场地的地震响应及其对上部结构的地震响应的影响规律。另外,利用非线性有限元软件建立了考虑冻土对温度的依存性及地基液化引起的等效剪切刚度变化的非线性计算模型,为后续的计算分析奠定了基础。分析表明,地表的地震响应由于土体非线化进展,随着输入地震波倍率的增大而变小,峰值频率变小。上部结构和地基的相互作用明显,地表面的增幅随着冻结深度的增加而降低,上部结构的地震响应和峰值频率变大。此可为季冻区冻土-结构动力相互作用研究提供参考。Abstract: Based on the shaking table tests on frozen soil-structure dynamic interaction system, the earthquake damage phenomenon of the superstructure and foundation of frozen soil site and the liquefaction phenomenon of sandy silt under earthquake excitation are reproduced by using the self-made indoor frozen soil freezing system, the seismic response of frozen soil sites with different freezing depths and its influence on the seismic response of superstructure are in vestigated. In addition, a nonlinear model considering the dependence of frozen soil on temperature and the change of equivalent shear stiffness caused by liquefaction of foundation is established by using the nonlinear finite element software, which lays a foundation for the subsequent calculation and analysis. The analysis shows that the seismic response and the peak frequency of the surface decrease with the increase of the input seismic waves due to the non-linear progress of the soil. The interaction between the superstructure and the foundation is obvious, the amplitude of ground surface decreases with the increase of the freezing depth, and the seismic response and the peak frequency of superstructure increase. The above results can provide reference for the study on frozen soil-structure dynamic interaction in seasonal frozen areas.