動態阻抗函數由土壤動態勁度與阻尼所構成，是以集中參數法分析廠房內振動基礎反應之必要參數。若未考慮材料阻尼及埋置深度之影響，則該動阻抗函數將高估振動振幅。理論上，任何能估算彈性半空間之彈性動阻抗函數之方法，均可利用「對應原理」求得黏彈性動阻抗函數。本文藉由材料阻尼理論之推演可知， Wolf 法屬於Voigt 介質模式之對應原理，而Gazetas 法則屬於等遲滯模式之對應原理。再由長×寬x深度為12mx6mx3m 之埋置基礎的單自由度系統反應分析發現: (1) 考慮材料阻尼使振動基礎之放大係數變小，但共振頻率則未改變; (2) 埋置效應使振動基礎之放大係數變小，且共振頻率增大; (3) Wolf 法之放大係數大於Gazetas法，但以後者較合理。 Dynamic impedance function is composed of the soil dynamic stiffness and damping ratio. It is the major parameter for the vibration analysis of foundations by the lumped model method.
Theoretically, all Viscoelastic dynamic impedance functions could be estimated from elastic ones by "correspondence principle". Based upon the theory of material damping, it is known that Wolfs method uses Voigt's model and Gazetas' method employs hysteresis
damping model. From the analysis ofa 12mx6mx3m (by length x width xdepth) embedded foundation in the single degree offreedom system, it is concl uded (I) that the material dampig gives influence only on the reducing of magnification factor, but not on the
resonance frequency, (2) that the magnification factor is reduced together with the resonance frequency being enhanced due to the embeddment effect and (3) that the Wolfs magnification factor is large.
關聯:
第七屆大地工程學術研究討論會論文集(第一冊)=Proceedings of the seventh conference on current researches in geotechnical emgomeeromg in Taiwan，頁225-232
