國道三號約378公里高雄中寮隧道的北端處，自民國八十九年開通以來隧道結構便持續的受到損毀，造成此現象之原因仍未明瞭，前人藉密集的水準測量及靜態測量發現，國道三號於旗山斷層以及龍船斷層之間路段的水平位移平均每年約有92 公厘、鉛直位移平均每年約有82 公厘，明顯大於台灣島每年82公厘的板塊擠壓縮短量，本研究之目的便是想釐清如此快速的變形與當地的構造活動特性之關係。 研究進行期間時逢國道三號隧道改善工程並對隧道北端進行開挖，本研究對中寮隧道整修開挖的露頭及附近區域進行詳細的地質調查，加上UAV攝影測量方法所製作的數值地表模型與正射影像，製作中寮隧道北端鄰近區域的地質圖與斷層分布圖。旗山斷層帶在隧道北端的斷層核心厚度約6公尺，位態約為042°/48 °S，斷層影響帶厚度約100公尺，斷層上盤開挖出露的岩層厚約80公尺，岩性以厚層砂岩與砂頁互層為主，下盤以厚層泥岩偶夾薄層風暴砂岩為主，且其中的泥岩中可發現三條延伸性佳的黑色剪切帶，並於中寮隧道北端出口西北方向約300公尺處的泥岩中發現厚層的斷層泥真厚至少67公尺，與前人斷層跡的調查比對後判斷為龍船斷層帶。在隧道毀壞嚴重處被彎曲的消防栓與放射狀分布的裂隙，顯示隧道的破壞是由於路面(或仰拱)的抬升以及隧道襯砌的壓縮所導致；隧道毀壞嚴重處的所在位置與旗山斷層核心重合。 中寮隧道北端鄰近區域的最大位移量梯度與旗山斷層帶的核心位置相符，露頭所觀察到的正移剪切面結合隧道裂隙觀察結果，推測隧道的損毀肇因於隧道下方岩層的向上推擠，因此本研究提出ㄧ地質模式，以旗山斷層為阻水層，在厚層泥岩排水不易的條件下，泥岩中的泥漿受擠壓進而向上推擠地表岩層產生位移，來解釋兩斷層間地塊的高位移量。 ;At the north end of Zhongliao Tunnel on National Highway No. 3, tunnel structure damage has been a problem as it open to the public since 2000 A.D. in Kaohsiung, Taiwan. The cause of this phenomena has not yet been identified. The predecessors have used dense leveling and GPS velocity survey to measure the surface displacement. The horizontal and the vertical movement of the area is about 92 mm and 82 mm per year between Chishan fault and Lungchuan fault which is greater than 82 mm per year caused by the shortening of plate tectonic movement in Taiwan island. Thus, the aim of this study would be to identify the relationship between rapid ground deformation and the structural characteristics of the study area. An excavation has been held at the north end of Zhongliao Tunnel during this study. Detailed geological surveys were carried out in the surrounding of the north end of Zhongliao Tunnel. In order to produce the Digital surface model (DSM) and Orthoimages for the geological map and fault map, the UAV photogrammetry method and VRS-RTK survey were taken in the study area. After the investigation, it was found that the fault core of Chishan fault zone is about 6 meters thick with the attitude of 042°/48 °S, and the thickness of the damage zone is about 100 meters. The outcrop is about 80 meters thick after the excavation on the hanging wall of Chishan fault which the lithology is mainly composed of sandstone and alternation with sandstone and shale. The lithology of the footwall is mainly composed of mudstone interbedded with some fine sandstone. Three branch faults were found in the footwall of Chishan fault. Compared the location with previous studies, I found Lungchuan fault zone has a thickness of 67 meters at least which is located 300 meters away from the north end of Zhongliao Tunnel in the northwest direction. After the examination in the tunnel, I consider the fractures to be the consequence of the uplifted pavement, and the compression of the tunnel lining in the seriously damaged area. The maximum displacement gradient in the Zhongliao tunnel is consistent with the location of the Chishan fault core. The observation of the normal shear plane and the tunnel fracture suggest that the tunnel damage is caused by the push of the rock below the tunnel. Therefore, this study proposes a geological model, with Chishan fault as the water-resisting layer. Under the condition that the thick mudstone is not easy to drain, the slurry in the mudstone is squeezed to push the surface rock layer to generate the high displacement of the block between two faults.
