隨著城市的快速發展，地下空間的使用率逐漸增加，鄰近工程的施工也日漸普及，既存隧道旁的基坑開挖工程就屬於上述鄰近施工的一種。而淺層的地下隧道多使用明挖覆蓋法(Cut-and cover)並以矩形（箱形）隧道形式建造，其優點在於方便施工且相關設施可最大化利用開挖空間。基坑開挖會對周遭的土壤產生解壓的作用，進而影響鄰近隧道產生內力及形變，以目前正在興建的捷運線段為例，當鄰近區域發生新建工程基地開挖時，捷運線段就監測到了不小的隧道徑向變形及軌道位移；台灣位在菲律賓海板塊及歐亞板塊的交界上，倘若開挖的過程中發生地震，則不僅僅只有隧道，開挖工程也會連帶受到影響，上述的變形量也可能會增加；但在過往的文獻中，卻鮮少探討地震對基坑開挖及鄰近隧道的影響，僅著重在開挖時既存隧道的變形行為而已。 本研究進行四組動態離心模型試驗，透過改變隧道與開挖面連續壁的間距，探討受震時兩者間相互影響的關係。試驗結果表示，當隧道愈鄰近開挖面連續壁時，連續壁的傾斜角度及頂部最大側向位移有增加的趨勢，隧道自身受到的形變量及沉陷量也較大；地表最大沉陷量發生於鄰近連續壁之背填土側，並且在隧道與連續壁間距最小時達到最大；隧道的變形量主要發生在開挖及架設支撐的過程中，與此相比，受振時的變形量較小。;The underground mass transit system network is developed rapidly in Taiwan urban area. The density of tunnel for subway or mass rapid transit is increasing year by year. Taiwan is located at the ring of fire, there are many active faults and earthquakes. The tunnel would be damaged and deformed induced by the strong ground motion. When the urban renewal plan is carried out in the future, if there is an existed tunnel nearby the deep excavation site, the unloading of soil would make the tunnel deform. The main objective of the present study is to verify the seismic efficiency of tunnel and excavation site, study the influence of distance between tunnel and retaining wall. Four groups of dynamic centrifuge tests are conducted under different distance. The test results show that the maximum lateral displacement and tilting angle of diaphragm wall and the deformation and settlement of tunnel become larger when the distance between tunnel and excavation site become smaller. The maximum ground settlement located in back-filled area, where is very close to continuous wall. The ground settlement become bigger when the distance of tunnel to excavation site become smaller. In addition, the deformation of tunnel is mainly caused by excavation, instead of shaking events.
