台灣位於環太平洋火山地震帶上，每年伴隨著颱風與地震侵襲。在豪雨期間，邊坡破壞為臺灣天然土石流災害的起源之一，常常造成極大的威脅與損失。國內以及國外學者近幾年投注了大量的心力與時間研究滑坡破壞的發生機制與條件，邊坡破壞會受降雨流量、流速、土體顆粒濃度、土體粒徑大小和土體顆粒種類等影響。對於邊坡破壞的發生原因包含土體飽和度、坡趾破壞、滲水流動和孔隙水壓上升等等…。本文採用日本筑波大學宮本邦明教授研發，主要以達西定律的滲流理論為基礎，探討邊坡破壞內部啟動機制與條件，觀察孔隙水壓在實驗過程的變化關係。使用壓克力水槽進行一系列的實驗，以直立壓克力水槽模擬土體在降雨入滲情況下孔隙水壓的變化與影響，並與土體在含有地下水形況下模擬滲流的情形作比較。最後觀察邊坡崩塌過成與速度場的變化對安全係數作分析。

Taiwan locates at the circum-Pacific belt and suffers from a lot of earthquakes, heavy rain and typhoons every year. Hence, slope failures frequently take place in Taiwan, especially during the typhoon season. Slope failure generally causes huge damages and it is one of the most severe natural disasters in Taiwan. Many studies were dedicated to investigate the initiation mechanism of slope failure, which are highly related to rainfall, soil type, particle size, soil type, and other hydrological conditions. The soil moisture, the failure of slope toe, the seepage flow and the sudden increase of the pore water pressure are the main factors associated with the slope failure. In the present study, we applied and extended the theory proposed by Prof. Miyamoto for investigating the triggering criterion of slope failure. We revisited the conditions and mechanism of slope failure, and performed experiments. It is observed that the toe failure is critical when there is no interstitial water flow. However, the interstitial water flow may cause the collapse of slope. While failure takes place, a sudden decrease of the pore water pressure is observed in experiment, and the water pressure increases rapidly. The process of the slope failure has been recorded by high-speed camera. Different scenarios have been performed by experiments. The safety factors, the velocity flow and the evolution of the fracture surface are detailed documented.

[1]Bernadiner, M.G. (1998), “A capillary microstructure of the wetting front.”, Transport in porous media, 30, 251–265.
[2]Cruden, D.M. and Varnes, D.J. (1996), “Investigation and Mitigation, in Turner, Keith A., and Schuster, Robert L., Landslides: investigation and mitigation.”, Transportation Research Board, National Research Council, National Academy Press, 247, 36–75.
[3]Huang, C.C., Ju, Y.J., Hwu, L.K. and Lee, J.L. (2009), “Internal soil moisture and piezometric responses to rainfall-induced shallow slope failures.”, Journal of Hydrology Engineering, 370, 39–51.
[4]Laloui, L., Klubertanz, G. and Vulliet, L. (2003), “Solid–liquid–air coupling in multiphase porous media.”, International Journal for Numerical and Analytical Methods in Geomechanics, 27, 183–206.
[5]Lourenço, S.D.N., Sassa, K. and Fukuoka, H. (2005), “Failure process and hydrologic response of a two layer physical model:Implications for rainfall-induced landslides.”, Geomorphology, 73, 115–130.
[6]Miyamoto, K. and Imaizumi, F. (2012), “A theoretical explanation of triggering condition of deep-seated landslide.”, The 3rd International Workshop on Multimodal Sediment Disasters in Japan, A-5-1–A-5-8.
[7]Orense, R.P., Farooq, K. and Towhata, I. (2004), “Deformation Behavior of sandy slopes during rainwater infiltration.”, Soils and Foundations, 44, 15–30.
[8]Okura, Y., Kitahara, H., Ochiai, H., Sammori, T. and Kawanami, A. (2002), “Lanslide fluidization process by flume experiments.”, Engineering Geology, 66, 65–78.
[9]Wang, G. and Sassa, K. (2003), “Pore-pressure generation and movement of rainfall –induced landslides: effects of grain size and fine-particle content.”, Engineering Geology, 69, 109–125.
[10]Wells II, W. G. (1987), “The Effect of Fire on the Generation of Debris Flows in Southern California.”, Geological Society of America, Review in Engineering Geology, 7, 105–114.
[11]Yang, H., Rahardjo H. and Leong E.-C. (2006), “Behavior of Unsaturated Layered Soil Columns during Infiltration.”, Journal of Hydrology Engineering, 11, 329-337.
[12]謝正倫 (1991)，「土石流災害防治與預警系統」，山坡地災害與防治研討會，1–26。
[13]洪如江 (1994)，「初等工程地質學大綱」，中華彩色印刷股份有限公司。
[14]詹錢登 (2000)，「土石流概論」，科技圖書股份有限公司。
[15]李文生 (2005)，「變飽和地下水流數值模式之研究」，國立臺灣大學土木工程學研究所博士論文。
[16]張家熏 (2006)，「探討淺層崩塌機制之大型試驗」，國立暨南國際大學地震與防災工程研究所碩士論文。
[17]謝明君 (2007)，「顆粒流的傳遞震波以及孔隙黏滯流體對土石流誘發起動之影響」，國立暨南國際大學土木工程學系碩士論文。
[18]李建誌 (2007)，「影像方法於量測顆粒流速度場之應用」，國立暨南國際大學土木工程學系碩士論文。
[19]雲世傑 (2007)，「探討豪雨中邊坡破壞發展過程之模型試驗」，國立暨南國際大學地震與防災工程研究所碩士論文。
[20]林芳慈 (2007)，「土層順間飽和上揚力效應之初步研究」，國立台北科技大學土木與防災研究所碩士論文。
[21]林洋震 (2008)，「顆粒流從斜坡到水平地形後堆積過程之研究」，國立暨南國際大學土木工程學系碩士論文。
[22]藍少村 (2008)，「降雨導致淺層邊坡破壞之模型試驗與分析」，國立成功大學土木工程研究所碩士論文。
[23]黃智煜 (2009)，「以實驗探討顆粒流之崩落流動狀態」，國立暨南國際大學土木工程學系碩士論文。
[24]駱建利 (2009)，「降雨導致邊坡破壞與土顆粒流出機制之研究」，國立成功大學土木工程研究所博士論文。
[25]林書達 (2012)，「以實驗探討溢流型潰壩的滲流與侵蝕」，國立成功大學水利及海洋工程研究所碩士論文。
[26]陳玟潔 (2012)，「壓力波對保水曲線特性之實驗影響評估」，國立成功大學水利及海洋工程研究所碩士論文。
[27]陳伯俊 (2013)，「快速顆粒流進入水中後之動態行為研究」，國立成功大學水利及海洋工程研究所碩士論文。