本研究主要目的在探討交通運輸工具，如車輛、大眾捷運或高鐵列車等行經於高架橋或橋樑時，交通荷重在橋－樁－土層系統之傳遞特性。基樁承受交通振動荷重後，能量迅速由樁身傳遞到樁尖，於承載層產生一振源，向四周擴散傳播，之後再經各種折射、反射等現象造成地表振動，另外，基樁振動除了樁尖所產生之壓力波外，樁身週遭土壤的相對運動或樁身周圍的土壤本身之相對變形均會產生剪力波，向外傳遞而出。因此希望直接透過橋墩下之基樁本身之改良設計以達到減振效果。為降低由基樁傳遞至承載層所產生之振波對鄰近結構物或精密廠房之振動影響，且考慮避免因減振而造成樁體之過大動態變位量，進而影響基樁上方結構物之安全性，本研究於模型樁上加裝高度不同之彈簧，改良為複合勁度減振彈簧之模型樁，以進行一系列模型試驗。藉由模型試驗探討改良樁對於樁尖在承載層中產生振波之減振成效、未改良樁與改良樁之樁周土壤中振波波傳衰減行為、衝擊加速度和彈簧勁度與樁體最大動態變位量之關係。完成砂土中改良樁加裝減振彈簧之動態性質探討後，將以不同的阻尼材料裝置於減振彈簧上，進行不同交通瞬間荷重的振動量測與分析，藉以探討減振基樁之垂直沉陷、力學特性與減振效益。 Vibrations caused by transportation vehicles passing through viaduct or bridge be transmitted from piers to pile foundations. The vibrations may generate waves in deep layer. The wave propagated from the bearing stratum then cause damages to the adjacent structures or high-tech production facilities. The purpose of this research is to investigate the most efficient way to reduce these vibrations. The main idea is to find out the best way to reduce the vibration that may cause some detrimental effects to the residences, adjacent structures or high-tech production facilities, and in the same time avoid large displacement of pile to occur. So, this research design two model piles. For one of the model piles, springs or damper are set on the pile head as the vibration suppression, and the other one is the original pile with no treatment. A series of model pile tests were carried out in laboratory to investigate the effects of vibration mitigation, behavior of the attenuation of wave propagation around model pile in the soil and the relationships among dynamic displacement of model pile, impact energy, spring constant and damping. After finishing the investigation on the dynamic propertirs of the piles which were improved by installing vibration suppression springs, this study may then add dampers on the springs and conduct the vibration experiment again to find out the dynamic properties and vibration suppression effects of the improved piles. 研究期間 : 9808 ~ 9907
