跨斷層國道三號田寮3號橋與中寮隧道北口段變形機制

國道三號田寮3號橋及中寮隧道分別跨越車瓜林斷層及旗山斷層，自民國89年通車迄今因持續的變形，在多次維修後仍無法有效改善。本研究利用分離元素法PFC3D (Particle Flow Code 3 Dimension)軟體建立斷層與橋梁、隧道互制模型，引入結構與風化泥岩材料的力學參數，模擬車瓜林斷層相對位移所引致之風化泥岩變形與結構互制行為。本研究顯示，車瓜林斷層於較深處之相對位移，造成風化泥岩之三角剪切帶(Trishear Zone)變形及其伴生之背衝斷層(Back Thrust Fault)，可以用來解釋國道三號田寮3號橋與中寮隧道北口段變形特徵。研究更進一步探究跨斷層結構物互制行為之參數分析，成果顯示風化泥岩材料性質、斷層傾角、風化泥岩厚度、改變斷層尖端位置及橋梁基礎埋置深度等不同條件，不僅影響風化泥岩三角剪切帶變形範圍，亦使結構產生不同之變形量，橋梁結構位於三角剪切帶(塑性區)時影響最大；另針對本工程案例在適當的簡化及討論變因條件下，不同橋梁上部結構型式受逆斷層作用之功能表現得知，多跨連續橋梁以非固接於墩柱之設計較固接連續梁及簡支梁有好的表現。

關鍵字

逆斷層；背衝斷層；三角剪切帶；分離元素法(PFC3D) ；斷層與結構互制

並列摘要

Tian-Liao No. 3 Viaduct on the National Highway No. 3, and Chung-Liao Tunnel cross Chekualin Fault and Chishan Fault respectively. Due to continuous deformation, they have not been improved efficiently even if repeated maintenance since it opened to traffic in 2000 till now. In this study, the software PFC3D (Particle Flow Code 3 Dimension) of the discrete element method was used to establish the model of the interaction between the fault and the bridge/tunnel. The mechanical parameters of the structure and the material of soil layer were also introduced to simulate the interaction behavior between the overburden soil and the structure which is caused by the relative displacement of Chekualin Fault. This study shows that the relative displacement at the deeper level of Chekualin Fault causes the deformation of the trishear zone at the shallow mudstone and accompanied back thrust fault, and it may be used as an interpretation for the deformation characteristics of Tian-Liao No. 3 Viaduct on the National Highway No. 3, or Chung-Liao Tunnel. This study further discusses the parametric analysis for the interaction behavior of the cross-fault structure. The results demonstrate some varying conditions such as material properties of overburden, fault angle, an overburden thickness, changing the fault tip's position and embedment depth of foundation, etc... They not only affect the deformation range of the trishear zone at upper overburden soil, but also different deformation of the structure; where the bridge structure located in the trishear zone (plastic zone) has the greatest influence. In addition, from the performance of the varying superstructure which is acted by the thrust fault, we may learn that the design of bridges with continuous multi-span and non-fixed-joint pier studs leads to better performance than that of fixed-joint continuous beams and simply beams.

並列關鍵字

thrust fault ； back thrust fault ； trishear zone ； discrete element method PFC3D ； fault and sturcture interaction

國際替代計量

跨斷層國道三號田寮3號橋與中寮隧道北口段變形機制

全文下載

主題瀏覽