台北捷運文湖線之振動量測與評估

Evaluation of Ground Vibration Induced by Taipei WenHu MRT Line

黃德政(TE-CHENG HUANG)

指導教授 ： 陳逸駿

中原大學/工學院/土木工程研究所/碩士(2011年)

https://doi.org/10.6840/cycu201100812

摘要

本研究主要針對台北捷運文湖線進行沿線之振動量測與衰減分析，以探討近域振動量與遠域波傳行為之評估。而文湖線之結構主要由橋樑-深基礎構成，土層可分為沖積層、卵礫石層及岩盤，但主要為軟弱土層。針對量測之結果分別探討列車速度、土層種類、結構型式、兩車交會及頻率因素之影響。
在近域振動量方面，列車之速度約落在55~66 km/h之間，車速對振動量之影響並不顯著。至於土層之影響，則有土層越堅硬，振動量越小之趨勢。從控制頻率之探討顯示U型樑之振動控制頻率落在高頻，而箱型樑則落在低中頻。當兩車交會時，引致之振動量提升1~2 dB。
在遠域振動波傳部分，沖積層之衰減係數落在0.0041~0.0053 (1/m)，卵礫石層落於0.0021~0.0023 (1/m)，岩盤為0.0030 (1/m)，有隨著剪力波速之增加，衰減係數減少之趨勢。影響距離之評估顯示利用Bornitz衰減公式回歸較為合理且有剪力波速上升影響距離越大之趨勢。然而與高鐵之波傳比較結果，發現本研究之波傳衰減情形與高鐵於路堤段較為相近，但與高鐵橋樑段則有些許差異。
另外本研究最後與中華顧問所建立之預估模式比較，顯示預估模式有近距離高估遠距離低估之現象。若考慮頻率因素而使用各頻率或低-中-高頻之衰減係數可得較可靠之預測值，而使用整體振動量不考慮頻率因素之誤差較大。

關鍵字

地盤振動 ； 衰減分析 ； 預估模式 ； 台北捷運文湖線 ； 高速鐵路

並列摘要

The purpose of this study is to evaluate the behavior of ground vibration induced by Taipei Wenhu MRT Line. Both near-field vibration and far-field wave propagation are examined for bridge with deep foundations. The geological conditions include alluvial soils, gravelly soils, and rock and mainly consist of soft ground. The effects of train speed, soil type, structure type, trains intersection, and frequency dependence are further analyzed.

For near-field vibration, the train speed, between 55 and 66 km/h, presents no significant effect to vibration. However, the effect of soil type to vibration can be observed. The results show that the harder the soil, the lower the vibration is. In addition, the vibration control frequency for U-beam superstructure is at high frequency range, while box-beam is at middle and low frequency ranges. Furthermore, the vibration level increases 1~2 dB when two trains intersect.

For far-field wave propagation, the wave attenuation coefficients of alluvium, gravel and rock are in the range of 0.0041~0.0053 (1/m), 0.0021~0.0023 (1/m) and 0.0030 (1/m), respectively. The attenuation coefficient is inversely related to the ground shear wave velocity. Moreover, the Bornitz equation shows reasonable results for vibration attenuation evaluation. The regression results show that the vibration influence distance becomes larger when ground shear wave velocity increases. Comparing the results of this study and high-speed trains, the results reveal that the wave propagation on Wenhu MRT Line is comparable to high-speed trains on embankment structures, but somewhat difference between Wenhu MRT Line and high-speed trains on bridge structures.

Finally, this study also examines the prediction model suggested by CECI Engineering Consultants, Inc., Taiwan. The measured results present that the prediction model over-estimates the near-field vibration and under-estimates the far-field vibration. This study suggests that it can be more accurate to predict the ground vibration using each frequency or the low-middle-high frequency ranges for analysis.

並列關鍵字

prediction model ； Taipei Wenhu MRT line ； high-speed trains ； attenuation analysis ； ground vibration

參考文獻

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