邊坡的滑動破壞常發生在大雨過後，其原因為雨水滲透進入邊坡表面並形成浸潤帶有關，使得土壤的基質吸力下降，間接影響邊坡的穩定性，導致邊坡於浸潤帶內發生淺層破壞的行為。
　　本研究選定南化山坡地並分別埋設土壤吸力計、土壤水分探測計、雨量觀測計、傾斜管，定期至觀測地點擷取數據與儀器維護。研究中將觀測地點收集到的數據，如土壤基質吸力與土壤體積含水量，繪製出相對應的變化關係並建構不同的土壤水分特性曲線，進一步探討監測結果與降雨的關係，並利用MATLAB求取土水特性曲線模型所對應的參數，供數值模擬分析使用。
FLAC數值分析程式內建之二相流模組分析兩種不同降雨強度與時間之下非飽和土壤邊坡的變化行為。邊坡模擬位移量變化與現地監測結果比較後發現兩者趨勢相符，顯示研究理論具一定的可靠性。

After rainfalls, sliding failure might happen on the slope because of the rainfall infiltration through the surface of the slope. Infiltration of rainfalls forms a wetting band which will reduce the matric suction and the stability of slope. It will cause a near flat shallow failure plane in the wetting band.
In this study, one shallow slope site (Nanhua) had been chosen to install equipments such as soil tensiometer, soil moisture sensor, inclinometer, and rain gauge. The monitoring instruments were checked and the data being collected monthly. The soil water characteristic curve was constructed by the fitting result of the matric suction and volumetric water content. The results were further examined to discuss the relationship between monitoring data and rainfalls. The software, MATLAB is used to find the constants in the soil water characteristic curves fitted by different models for numerical analysis purpose.
The two-phase flow module in FLAC is used for analyzing the behavior of unsaturated soil slope under two different kinds of rainfall intensity and duration. The slope displacement simulation and field monitoring results were compared. The results show that the trends in both cases match well.

1. 王曼穎，「非飽和土壤邊坡之監測與分析」，碩士論文，國立成功大學土木工程研究所(2012)。
2. 林鴻彰，「不飽和土壤邊坡基質吸力與位移之監測及邊坡穩定分析」，碩士論文，國立台灣科技大學營建工程系(2008)。
3. 陳志昌，「FLAC程式應用於土壤邊坡穩定分析」，碩士論文，國立中央大學應用地質研究所(2002)。
4. 陳奕豪，「侯硐地區土石流材料在不飽和狀態下剪力強度研究」，碩士論文，國立台灣大學土木工程研究所。
5. 陳顯哲，「降雨情況下不飽和風化土壤邊坡含水量於空間與時間之分佈行為」，碩士論文，國立高雄第一科技大學營建工程系碩士班(2012)。
6. 高嘉彬，「不飽和土壤邊坡基質吸力與位移之監測及滲流分析」，碩士論文，國立台灣科技大學營建工程系(2007)。
7. 黃柏堯，「非飽和土壤邊坡滑動監測安裝研究」，碩士論文，國立成功大學土木工程研究所(2011)。
8. 彭建平與邵愛軍，「基於MATLAB方法確定VG模型參數」，水文地質工程地質，第六期，pp. 25-28 (2006)。
9. 馮正一、張育瑄，「不飽和邊坡之降雨入滲模擬」，94年水資源管理研討會(2005)。
10. 蔡孟棻，「以土壤水分特性曲線評估不飽和邊坡穩定性」，碩士論文，國立台灣科技大學營建工程系(2005)。
11. 盧祈均，「不飽和風化岩土壤邊坡於降雨時力學行為與時間之關係機制」，碩士論文，國立高雄第一科技大學營建工程系碩士班(2012)。
12. 鄭清江，「以傾斜管變位及極限穩定分析進行華梵坡地穩定機制之探討」，華梵學報，第九卷(2003)。
13. 謝平城、王瀚衛，「降雨滲流對邊坡穩定的影響」，水土保持學報第36卷第2期，pp. 135-142(2004)。
14. Aitchison, G.D.,and Donald, I.B., “Effective stresses in unsaturated soils,” Proceedings, The 2nd Australia-New Zealand Conference of Soil Mechanics, pp. 192-199 (1956).
15. Brooks, R.H., and Corey, A.T., “Hydraulic properties of porous media,” Hydraulic Paper, No. 3, Colorado State University, Fort Collins, CO (1964).
16. Brooks, R.H., and Corey, A.T., “Hydraulic properties of porous media,” Journal of Irrigation and Drainage Division, American Society of Civil Engineers, Vol. 92, No. IR2, pp. 66-88 (1966).
17. Croney, D., and Coleman, J. D., “Soil thermodynamics applied to the movement of moisture in road foundations,” Proceedings, 7th Int. Cong. Appl. Mech., Vol. 3, pp. 163-177 (1948).
18. Darcy, H., Les fontaines publiques de la ville de Dijon, Dalmont, Paris (1986).
19. Davies, O.C., Rouainia, M., and Glendinning, S., “Numerical prediction of seasonal pore water pressure fluctuations using FLAC tp flow,” Proceedings, The 1st European Conference on Unsaturated Soils, pp. 817-822 (2008).
20. Fredlund, D.G., and Xing, A., “Equation for the soil-water characteristic curve,” Canadian Geotechnical Journal, Vol. 31, No. 3, pp. 521-532 (1994).
21. Fredlund, D.G., Xing, A., and Huang, S., “Predicting the permeability function for unsaturated soils using the soil-water characteristic curve,” Canadian Geotechnical Journal, Vol. 31, No. 3, pp. 521-532 (1994).
22. Fredlund, D.G., Xing, A., Fredlund, M.D., and Barbour, S.L., “The relationship of the unsaturated soil shear strength function to the soil-water characteristic curve,” Canadian Geotechnical Journal, Vol. 32, No. 3, pp. 440-448 (1995).
23. Fredlund, D.G., Morgenstern, N.R., “Stress state variables for unsaturated soil,” Journal of Feotechnical Engineering, ASCE, Vol. 103, No. 5, pp. 447-466 (1977).
24. Fredlund, D.G., Morgenstern, N.R., and Widger, R.A., “The shear strength of unsaturated soils,” Canadian Geotechnical Journal, Vol. 15, No. 3, pp. 313-321 (1978).
25. Fredlund, D.G., and Rahardjo, H., Soil Mechanics forUunsaturated Soils, John Wiley & Sons, Inc., New York (1993).
26. FLAC User’s Manual Version 5, Fluid –Mechanical Interaction, Itasca Consulting Group, Inc., Inneapolis, Minnesota, USA, pp. 2.1-2.53 (2005).
27. Gardner, W.R., “Some steady state solutions of the unsaturated moisture flow equation with application to evaporation from a water table,” Soil science journal, Vol. 85, No. 4, pp.228-232 (1958).
28. Ho, D.Y., and Fredlund, D.G., “Increase in strength due to suction for two Hong Kong soils,” Proceedings, ASCE Speciality Conference on Engineering and Construction in Tropical and Residual Soils, Hawaii, pp. 263-296 (1982).
29. Leong, E.C., and Rahardjo, H., “Review of soil-water characteristic curve equations,” Journal of Geotechnical and Geoenvironmental Engineering, Vol. 123, No. 12, pp. 1106-1117 (1997).
30. Lu, N., and Likos, W.J., “Suction stress characteristic curve for unsaturated soils,” Journal of Geotechnical and Geoenvironmental Engineering, Vol. 132, No. 2, pp. 131-141 (2006).
31. Lam, L., Fredlund, D.G., and Barbour, S.L., “Transient seepage model for saturated-unsaturated soil system: a geotechnical engineering approach,” Canadian Geotechnical Journal, Vol. 24, No. 4, pp. 565-580 (1987).
32. Mckee, C.R., and Bumb, A.C. “Flow-testing coalbed methane production wells in presence of water and gas,” SPE Formation Evaluation, Vol. 2, No. 4, pp. 599-608 (1987).
33. Ng, C.W.W., and Shi, Q., “A numerical investigation of the stability of unsaturated soil slopes subjected to transient seepage,” Computers and Geotechnics, Vol. 22, No. 1, pp. 1-28 (1998).
34. Rahardjo, H., Lee, E.C., Leong, E.C., and Rezaur, R.B., “Response of a residual soil slope to rainfall,” Canadian Geotechnical Journal, Vol. 42, No. 2, pp. 340-351 (2005).
35. Rahardjo, H., Satyanaga, A., and Leong, E.C., “Unsaturated soil mechanics for slope stabilization,” Proceedings, The 5th Asia Pacific Conference in Unsaturated Soils, pp. 103-117 (2011).
36. Rahardjo, H., Lim, T.T., Chang, M.F.,and Fredlund D.G., “Shear strength characteristics of a residual soil,” Canadian Geotechnical Journal, Vol. 32, No. 1, pp. 60-77 (1995).
37. Sun, D.M., Zhu, Y.M., and Zhang, M.J., “Study on numerical for water-air two-phase flow in unsaturated soil,” Chinese Journal of Geotechnical Engineering, Vol. 29, No. 4, pp. 560-565 (2007).
38. Sillers, W.S., and Fredlund, D.G., and Zakerzadeh, N., “Mathematical attributes of some soil-water characteristic curve model,” Geotechnical and Geological Engineering, Vol. 19, No. 3-4, pp. 243-283 (2001).
39. Terzaghi, K., “The shear resistance of saturated soil,” Proceedings, The 1st Int. International Conference on Soil Mechanics and Foundation Engineering. Vol. 1, pp. 54-56 (1936).
40. van Genuchten, M.T., “A closed-form equation for predicting the hydraulic conductively of unsaturated soils,” Journal of Soil Science Socieety of America, Vol. 44, No. 5, pp. 892-898 (1980).
41. Vanipalli, S.K., and Fredlund, D.G., “Empirical procedures to predict the shear strength of unsaturated soils,” Proceedings, The 11th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, pp. 93-96 (1999).
42. Weir, G.J.,and Kissling, W.M., “The influence of airflow on the vertical infiltration of water into soil,” Water Resource Research, Vol. 28, No. 10, pp. 2765-2772 (1992).
43. Zhan, L.T., and Ng, W.W., “Analytical analysis of rainfall infiltration mechanism in unsaturated soils,” International Journal of Geomechanics, Vol. 4, No. 4, pp. 273-284 (2004).