| 摘要: | 台灣地區地狹人稠，工程建設高度發展，因此經常發生施工振動致使居民生理和心理上的不適應，甚或影響周遭園區廠房的機械設備與精密儀器正常運轉及使用，更嚴重者導致鄰近結構物損壞之情況。近年來在都會區人口密集成長、交通道路或地表與地下捷運之擴充興建、以及老舊建物都市更新計畫等工程，可預期會有更多現地施工場址毗鄰住宅建築物及居民，因此在環境振動問題上會出現更多爭議及困擾，對於容許之地表振動的要求與限制愈趨嚴格下，設法改善地盤環境振動問題，早期發展相關阻隔措施以減低振動影響，是目前所關心之研究課題。 本研究首先蒐集整理國內外現有對人、精密機械與結構物之振動公害管制準則進行比較分析。針對不同施工場址進行現地振動量測，包括動力夯實、打設PC樁、鋼板樁、H型鋼樁、礫石樁與隧道開炸等施工，以及振動機具敲擊混凝土地面所造成之地盤振動衰減特性，進行振動數據資料之整理與分析。同時在現地施工場址進行隔減振試驗，以評估其減振成效。也於建築結構物不同樓層處裝設振動感應器，以量測結構物本身受到不同類型施工振動影響時之振波傳遞反應。分析方法採用地盤振動衰減率、傅氏譜及反應譜等方法，亦利用新近發展的希爾伯特-黃轉換之三維(能量-頻率-時間)頻譜分析法，來探討施工振動能量於時間域及頻率域上之完整分佈狀況。並對相關振動管制準則與實際振動量測案例進行檢核與驗証，且建議較具工程實用性之施工安全距離及設計反應譜，供各界參考使用。 最後以數值模擬分析動力夯實與打設PC樁施工之暫態波地盤振動模式，並與現地實測值比較討論，且探討淺層槽溝之效用，分析與建立施工引致地盤振動量之預測模式。主要使用ABAQUS有限元素分析軟體，經由適當地選擇振源模式、邊界條件、網格建構、材料參數與土壤阻尼之模式，則可相當程度地反應現地施工之地盤振動行為。 Taiwan is heavily populated in some restricted area. Engineering civil structures are highly developed in this country. Construction activities are often close to the surrounding living and working environments. Ground vibrations due to construction often caused residents uncomfortable or the precision machinery operation abnormal or, more seriously, the adjacent structures damaged. First, the various worldwide vibration criteria was collected, compared and analyzed. Then, this investigation performs a series of field measurements of ground vibrations due to various constructions, including dynamic compaction, PC pile driving, vibratory sheet-piling, H steel piling, gravel column piling, tunnel blasting and vibrating machine striking concrete pavement. The triaxial velocity sensors were also installed on the different floors of various structures which located in different distances from the construction sites. The measured vibration data was used to investigate the vibration characteristics of ground and structures. The characteristics include the distance attenuation relation, Fourier and response spectra of vibration record, predominant frequencies of different structures, and the vibration propagation effect from the ground through the building structures. A newly developed method called Hilbert-Huang Transform (HHT) was also used to analyze the three dimensional relation of amplitude-frequency-time for vibration signals. The energy distribution characteristics of construction vibrations in frequency and time domains have been surveyed and discussed in detail. An empirical method for evaluating the safe construction distance to adjacent building structures was presented based on the attenuation relation and the proposed building vibration criterion. Vibration response spectra were also suggested for use with the spectral analysis method to determine more accurately the safe construction distance. The study also discussed the isolation and barrier effects of the trench and sheet pile on the vibration propagation by the measured data. Finally, based on the numerical simulation using ABAQUS software (finite element analysis program) and choosing appropriate vibration source, boundary conditions, material properties of hammer, piles and soil, the transient behaviors of ground vibrations induced by dynamic compaction and pile driving in situ are quite reasonably displayed. |
