随着地震模拟振动台数量越来越多,其运行对环境的振动影响受到极大关注。通过现场实测和分析,深入探讨了振动台运行对周围场地的振动影响,结果表明:如果将振动台基础简化为单自由度质点-弹簧-阻尼模型,地基土提供弹性力和阻尼,振动台的运行视为施加于基础的动力荷载,由此得到的计算结果与实测基本吻合。通过扫频试验获取了基础振动幅频响应曲线并进而确定了基础自振频率。试验研究结果显示,当振动台台面产生峰值为1.5g加速度时,基础及实验室内地面加速度最大值仅有5gal,不及台面的0.4%;振动从基础向周边场地传播按指数规律衰减,一般不会对周围建筑安全和人员舒适性造成不良影响。
Abstract
The free-field vibration induced by large shaking-table was studied by analysis and measurement. The mass-spring-damping model is reasonable that the lumped mass is afforded by shaking-table foundation while the restoring force and damping force are afforded by foundation soil. Based on the displacement frequency response curve by using sweep experiment, the natural frequency of the foundation was obtained. The shaking-table induced free-field acceleration is only 5 gal while the table acceleration is 1.5 g. The vibration attenuation law with distance follows the exponential relationship. The full load operation of the shaking table is no significant impact on human bodies’ health and safety of buildings without layout of precise instruments and high-tech facilities.
关键词
地震模拟振动台 /
振动影响 /
质点-弹簧-阻尼模型 /
衰减规律
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Key words
shaking-table /
vibration influence /
mass-spring-damping model /
attenuation law
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参考文献
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