以離心模型試驗探討沉箱碼頭之受震反應及復建補強對策;Centrifuge modeling on seismic responses of caisson type quay wall with reformation backfill during earthquake

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Title:	以離心模型試驗探討沉箱碼頭之受震反應及復建補強對策;Centrifuge modeling on seismic responses of caisson type quay wall with reformation backfill during earthquake
Authors:	張志鵬;Zhang,Zhi-peng
Contributors:	土木工程研究所
Keywords:	背填土改良;沉箱振動模態;主頻;沉箱旋轉中心;沉箱式碼頭;超額孔隙水壓;rotation center of quay wall;predominant frequency;caisson type quay wall;excess pore pressure;vibration modes of quay wall;reformation backfill soil
Date:	2012-08-28
Issue Date:	2012-09-11 18:05:29 (UTC+8)
Publisher:	國立中央大學
Abstract:	現今的港灣碼頭多設置於人工回填地，但此種地盤飽和度高且鬆軟，受震時容易產生土壤液化的現象，當液化發生時，擋土的沉箱結構受到慣性力的影響朝海側位移，使碼頭後方的背填土產生沉陷、滑動等現象，造成其後線作業區的損壞因而長期停用，導致龐大的經濟損失。本研究以離心模型試驗模擬重力式沉箱碼頭的受震反應，並探討其振動模式對於沉箱碼頭系統的沉箱–土壤互制行為的影響，再以改良後的背填土進行試驗，觀察其對沉箱碼頭系統受震反應的影響。本研究將縮尺後的沉箱碼頭模型置於試驗箱，以80 倍純水黏滯度的黏滯液體模擬孔隙水，在80g 的離心力場下進行試驗，並在試體內部配置加速度計、孔隙水壓計、土壓力計等量測各物理量的變化，試體外部則以線性差動變壓器（LVDT）量測其變位。試驗結果顯示：(1)以黏滯液體代替水作為飽和溶液，可以有效的模擬出更真實的動態反應，例如孔隙水壓的激發與消散等；(2)改良後的試體會阻斷基礎砂層的排水路徑，在振動時會使基礎層的超額孔隙水壓難以消散，因而容易液化；(3)背填土經過改良後可以有效降低其沉陷量，改良區域沉陷量較未改良相比僅有四分之一；(4)經過改良的試體，受到旋轉模態影響較大，其旋轉中心有朝海側發展的趨勢。The harbor often set in the artificial fill ground. But such of this siteshave high saturation and loose sand. So when it shake, the soil willdamage by liquefaction easily. Liquefaction will make the quay wallmove toward the sea side by inertial force, and settlement of the backfillbehind the quay wall. So that the area of working will out of service longtime, induce huge disadvantage of economic.In this research use the centrifuge model simulate the caisson typequay wall’s response during earthquake. And discuss the effect about thesoil-structure inter action from mode of shaking. Then using thereformation soil replace the loose backfill and observe the result of theresponse during earthquake.The conclusion is: (1)using viscous fluid replacing water is a betterapproach to simulate the real response of quay wall during earthquake(2)The reformation soil will cut the path of drainage of the void fluid ofthe foundation soil under the quay wall. (3)The reformation backfill willreduce the settlement effectively (4)The rotation mode of shaking willaffect the test with reformation backfill more than the test withoutreformation backfill.
Appears in Collections:	[Graduate Institute of Civil Engineering] Electronic Thesis & Dissertation

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