台南科學園區地盤振動試驗與其衰減特性之研究

In-Situ Tests of Ground Vibration and the Assessment of Ground Vibration Attenuation in the Tainan Area of Southern Taiwan Science Park

黃宗宸(Tsung-Chen Huang)

指導教授 ： 陳正興

國立臺灣大學/工學院/土木工程學研究所/博士(2010年)

https://doi.org/10.6342/NTU.2010.00212

摘要

南科台南園區為我國高科技產業發展之重要基地，園區內之高科技廠房與精密設備，對於周遭環境振動相當敏感。而台灣高鐵列車行駛路線恰穿越南科台南園區，其所引致地盤振動對周圍環境之影響也因而成為各界關切之焦點。本研究彙整歷年來於南科台南園區內進行之現地振動試驗與行車量測結果，以探討園區內之地盤振動與衰減特性。於本研究中共包含九次現地試驗與行車量測，其中現地試驗包括四次重錘落擊振動試驗與五次起振器強迫振動試驗，分別於素地、淺基礎、單樁基礎與群樁基礎上，以重錘落擊（不同錘重、不同落距）與起振器運轉(出力100kN與200kN)之方式產生振源，量測所引致地盤振動隨傳播距離之衰減關係；而於行車振動量測方面，則包含十車次高鐵列車以及四車次重型貨車行駛所引致地盤振動之量測與分析，探討高鐵列車與重型貨車行駛所引致之地盤振動特性及其隨傳播距離之衰減關係。
根據分析結果顯示，台南園區內地盤之自然振動頻率約在3.1~5Hz；重錘落擊所引至地盤振動之顯著頻率主要集中於3.1~10Hz附近，當錘擊能量增加時，顯著頻率有偏向於低頻之趨勢，且會得到相對較低之衰減係數；高鐵列車行駛所引致較大之地盤振動發生在車行方向(與測線垂直方向HT)與鉛垂向(V)上，於車速270km/hr時所引致地盤振動之顯著頻率集中在3.1Hz、6.3Hz與10Hz附近；重型貨車行駛所引致較大之地盤振動則發生在垂直車行方向(與測線平行方向HL)與鉛垂向(V)上，引致地盤振動之顯著頻率則集中在10Hz~12.5Hz附近；而各方向上之地盤振動衰減係數，大致皆有隨振動頻率增加而提高之趨勢，其主要差異僅在於各種振源所得衰減係數大小與隨頻率變化趨勢之不同。
綜合比較各種試驗與量測之分析結果，顯示在相同地盤條件下，所引致地盤振動之顯著頻率、振幅大小與振動衰減特性，會隨振源之型式、作用能量大小、振源位置底下基礎型式、基礎與土壤接觸面積大小、基礎尺寸與構材勁度等條件不同而有顯著之差異；由研究結果亦發現，重型貨車行駛所引致之地盤振動量不容忽視，建議於高科技廠房設計規劃時，實有必要同時考慮各式行車振源所引致地盤振動之影響，有必要時須進行被動式之隔減振設計。

關鍵字

南科台南園區 ； 高速鐵路 ； 重型貨車 ； 重錘落擊試驗 ； 起振器強迫振動試驗 ； 地表振動 ； 振動衰減係數

並列摘要

The Taiwan High Speed Rail (THSR) passes through the Tainan Area of Southern Taiwan Science Park (STSP) where the high-tech fabs inside are very sensitive to ground vibrations. In order to characterize the attenuation of ground vibration with distance and characteristics of ground vibration, a series of small-scaled in-situ vibration tests and traffic-induced ground vibration measurements were conducted at sites in STSP. The tests including four drop hammer tests and five shaking tests which were performed on the ground surface, on shallow foundation (footing), on single pile foundation, and on proto-type pile foundation, respectively. For drop hammer tests, hammer weights of 80, 120, 220, 260, 430kN and drop heights of 0.5m~3.0m were adopted to generate different levels of ground vibration. For shaking tests, exciters that can generate harmonic loads up to 100 or 200kN were used for ground vibration tests. As for the traffic-loading induced ground vibration measurements, a total of ten high speed trains running with various speeds and four cases for heavy trucks running were measured.
In this study, results of all drop hammer tests and shaking tests are summarized and compared with those of in-situ measurements of ground vibrations induced by heavy trucks and THSR trains. Analysis results show that the natural frequency of STSP site is about 3.1Hz to 5Hz. The main frequency of drop hammer tests is about 3.1Hz to 10Hz. The heavier the hammer weight and the larger the energy of impact loading, the lower the significant frequency and the smaller the attenuation coefficients will be. The ground vibrations induced by THSR trains will have larger responses in the vertical direction and the THSR route direction. The main frequency of the high speed train running through STSP by the speed of 270km/hr is about 3.1Hz, 6.3Hz, and 10Hz. The larger levels of ground vibrations induced by heavy trucks are found in the vertical direction and the perpendicular direction of route. The main frequency of heavy trucks running is about 10Hz to 12.5Hz. Attenuation coefficient of ground vibration in each direction generally increases with frequency. In addition, the ground vibrations induced by different type of sources will have different characteristics. The ground vibrations induced by high-energy source and line-load source tend to be decayed slower with traveling distance.
From this study, it concludes that the dominant frequency, amplitude, and attenuation coefficients of ground vibration at the test site are influenced by different source types, energy level, foundation type, interface area between soil and foundation, as well as the foundation size and stiffness. Conclusions also show that the levels of ground vibration induced by heavy truck are significant at small distances. Therefore, for the design of high-tech fabs in STSP, both the ground vibrations induced by the THSR and the heavy trucks have to be considered to meet their operational requirements.

並列關鍵字

Southern Taiwan Science Park ； Taiwan High Speed Rail(THSR) ； truck loading ； drop hammer test ； shaking test ； ground vibration ； attenuation coefficient

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