本研究以沉泥質砂土在長、寬、高分別為2.55 m、1.0 m、2.0 m的流槽中進行模型邊坡降雨實驗，試驗土層厚度0.385 m，坡角為30°，探討邊坡在豪雨中的破壞機制、土砂流出特性及降雨強度改變所造成之影響。於邊坡的坡趾、坡中與坡頂埋設有土壤水份計、孔隙水壓計及雙軸向荷重計，用以監測降雨時邊坡內部含水量、孔隙水壓及土壓力變化，並藉由邊坡模型匯流口所收集邊坡破壞後所排出雨水及土砂之混合物，來觀察其排放率與混合物體積濃度變化情形。
研究各槽溝位置所量測之土壤含水量(ω)與時間(t)關係曲線與後退式破壞的相關性。岩土交界面之土壤含水量與時間曲線上的第一反曲點與坡趾滲水、累積排砂量反曲點之發生時間具有密切的關係。溼潤前線到達不透水層的時間約略與邊坡破壞(大量排出土砂)之起始點一致，研究邊坡在臨界破壞狀況下顯示，不論距坡趾之破壞距離和降雨強度，土層表面下0.29 m的區域維持不飽和狀態(Sr≦40%-60%)，量測各降雨強度下模型試驗臨界破壞狀態時，沿著斜坡與不透水層界面的土壤含水量在原本坡趾的周遭或因後退式破壞崩塌的暫時坡趾周遭，在臨界破壞狀況接近飽和狀態(Sr≦80%-100%)，由邊坡內部不一致的飽和狀態顯示沿著斜坡與不透水層界面的滲流是引起後退式的淺層崩壞主要作用。

A series of artificial rainfall tests were performed on sizes were 0.385 m, thick sandy slopes with a slope angle of 30°. Wooden sand boxes with 2.55m long, 1.0 m wide and 2.0 m high, was used with soil moisture sensors and a data acquisition system to monitor the interior soil moisture response to the rainfall infiltration. The present study features the measurement of solid and water discharge from the slope subjected to rainfall. This substantiates the investigation into the relationship between the soil moisture response and the solid discharge (or waste) process.
Characteristics of the soil water content (ω) vs. time (t) curves measured at various locations within the slope were examined and their relevance to the retrogressive shallow slope failure was studied. Scenarios of wet front and water table developments can be described using the times at which the inflection points occur on these  vs. t curves. The threshold time defined by the inflection point of the moisture response curve was related to some critical failure states, namely, the minor toe wash-out, the slope toe failure, and proceeded slope failures represented by a slumped mass about 20% of the total slope mass. It was found that some threshold times can be used as precursors for the initiation of rainfall-induced shallow slope failures. An investigation into the uniformity of  (or degrees of saturation, Sr) in the slope at the critical failure states shows that the 0.29 m-below-surface zone remains unsaturated with Sr ≒ 40%-60%, regardless of their distances from the toe and the rainfall intensity. Similar patterns of  distributions along the slope at the critical failure states were measured at the soil-bedrock interface for all intensities of rainfall. The distribution of  (or degree of saturation, Sr) along the soil-bedrock interface at the critical failure states was nonuniform with a near-saturation state (Sr≒80%-100%) around the ‘original’ toe or around the transient ‘toe’ upstream of the slumped mass induced by the retrogressive failure of the slope, regardless of the rainfall intensity. The nonuniformity of  within the slope and the saturated state at the transient ‘toe’ upstream of the slumped mass all suggest that an interflow along the soil-bedrock interface may play a major role in the retrogressive shallow slope failure.

1.Aleotti, P. (2004) “A warning system for rainfall-induced shallow failures” Engineering Geology, Vol. 73, pp. 247-265.
2.Brand, E.W., (1982) ”Analysis and Design in Residual Soils ” Proceedings of the ASCE Geotechnical Engineering Division Specialty Conference Engineering and Construction in tropical and Residual Soils, Honolilu, Hawaii, pp. 89-141, January 11-15.
3.Cai, F. and Ugai, K. (2004) “Numerical analysis of rainfall effects on slope stability” International Journal of Geomechanics, ASCE, pp. 69-78.
4.Eckersley,J.D.,1990.”Instrumented laboratory flow slides. ”Geotechique 40, No.3,pp.489-502
5.Johnson, K.A., and Sitar, N. (1987) ”DebrisFlow Initiation; An Investig ation of Mechanisms ” Department of Civil Engineering Report No.UCB/GT/87-02, University of California ,Berkeley, California,179 pp.
6.Keefer, D.K., Wilson, R.C. Mark, R.K. BRabb, E.E., Brown Ⅲ, W.M., Ellen, S.D., Harp, E.L., Wieczorek, G.F., Christopher, S.A. and Zatkin, R.S. (1987) “Real-time landslide warning during heavy rainfall” Science, Vol. 238, pp. 921-925.
7.Lavigne, F. and Suwa, H. (2004) “Contrasts between debris flows, hyperconcentrated flows and stream flows at a channel of Mount Semeru, East Java, Indonesia” Geomorphology, Vol. 61, pp. 41-58.
8.Lenhman, O.R. and Ahuja, L.R., (1985) “Interflow of water and tracer chemical on sloping field plots with exposed seepage faces” Journal of Hydrology, Vol. 76, pp. 307-317.
9.Lourenco, S. D. N., Sassa, K. and Fukuoka, H. (2006) “Failure process and hydrologic response of a two layer physical model : Implications for rainfall-induced landslides” Geomophology, Vol. 73, pp. 115-130.
10.Lumb, P. (1975) “Slope failures in Hong Kong” Q. J. Engng. Geol., Vol. 8, pp. 31-65.
11.Nishigaki, M., Tohari, A. and Komatsu, M. (1999) “Predicting rainfall-induced slope failures from moisture content measurement” Proceedings of International Symposium on Slope Stability Engineering, Matsuyama, Shikoku, Japan, Yagi, N., Yamagami, T. and Jiang, J-C. (eds.), Balkema, Rotterdam, Vol. 1, pp. 465-470.
12.Okura, Y., Kitahara, H., Ochiai, H., Sammori, T. and Kawanami, A. (2002) “Lanslide fluidization process by flume experiments” Engineering Geology, Vol. 66, pp. 65-78.
13.Orense, R.P., Shimoma, S., Maeda, K. and Towhata, I. (2004) “Instrumented model slope failure due to water seepage” Journal of Naturnal Disaster Science, Vol. 26, No. 1, pp. 15-26.
14.Sammori, T. and Kawanami, A. (2002) “Landslide fluidization process by flume experiments” Engineering Geology, Vol. 66, pp. 65-78.
15.Springman, S.M., Jommi, C. and Teysseire, P. (2003) “Instabilities on moraine slopes induced by loss of suction : a case history” Geotechnique, Vol. 53, No. 1, pp. 3-10.
16.Varnes, D.J., (1978) “Slope movement types and processes ;in Landslides, analysis and control” National Academy of Sciences, Schuster, R.L and Krizek, R.J. (eds.) Special Report 176, Washington, D.C., p.p. 11-33.
17.Wang, G., Sassa, K. (2003) “Pore-pressure generation and movement of rainfall –induced landslides: effects of grain size and fine-particle content” Engineering Geology, Vol. 69, pp.109~125.
18.Wörman, A. (1993) “Seepage-induced mass wasting in coarse soil slopes” Journal of Hydraulic Engineering, Vol. 119, No. 10, pp. 115-1168.
19.朱奕璋（2005），“土石流源頭崩塌之大型試驗與分析”，碩士論文，國立暨南國際大學地震與防災工程研究所。
20.李金龍 (2006)， “探討降雨與淺層崩塌關係之大型試驗”,，碩士論文，國立暨南國際大學地震與防災工程研究所。
21.范正成、謝宏元(1991) ，“田間降雨機之回顧、研究及比較”，中華水土保持學報，第22卷，第一期，第9-20頁。
22.范正成、吳明豐(1996) ，“台灣地區田間人工降雨機之研究、操作、率定及分析”，中華水土保持學報，27(1)，第359-425頁。
23.張家熏 (2006) ，“探討淺層崩塌機制之大型試驗” ，碩士論文，國立暨南國際大學地震與防災工程研究所。
24.雲世傑 (2007) ， “探討豪雨中邊坡破壞發展過程之模型試驗”，碩士論文，國立暨南國際大學地震與防災工程研究所。
25.黃景川、 吳肇峰、郭峰志、張政茂 (1995) ， “以黏土為背填之加勁擋土牆大型試驗”，第六屆大地工程學術研討會論文集，pp.281-288。
26.黃景川(1999），“土壤力學”，台北市：三民書局。
27.詹錢登(2000) ，“土石流概論”，科技圖書股份有限公司。
28.詹錢登、李明熹（2004），“土石流發生降雨警戒模式”，中華水土保持學報，第35期，第3卷，第275~285頁。