集集地震後，紅菜坪地區發生範圍涵蓋數百公頃之地層滑動，地
滑區崩積層最厚處達82 公尺。為瞭解紅菜坪地區滑動機制，紅菜坪
地區佈設了GPS、光纖感測器以及傳統傾斜計進行地層移動監測，並
裝設了開口式水壓計，利用人工以及自動紀錄水位指示器長期監測水壓變化。其中三處裝設於崩積層與岩盤交界面之水壓計，紀錄到暴雨期間孔隙水壓不昇反降之異常反應。本研究根據2005 年11 月1 日至2006 年11 月30 日降雨-孔隙水壓變化曲線，分別針對季節性孔隙水壓變化以及暴雨期間之反應進行分析與討論。就季節性變化而言，岩盤與崩積層交界面孔隙水壓乾季略降而濕季略昇，孔隙水壓變化不超過30 kPa，季節性孔隙水壓反應屬於單峰型至微變化型。降雨期間，孔隙水壓變化正常反應為隨降雨孔隙水壓逐漸上升，降雨減緩則孔隙水壓隨之下降，上邊坡崩積層厚度較薄者(30m 左右)，降雨孔隙水壓上升幅度較大(約10kPa)，邊坡中段崩積層厚度較厚者(60~80m 左右)，孔隙水壓較不受降雨影響而變化幅度較小(不到3kPa)，降雨孔隙水壓反應則有單峰對稱與非對稱型、多峰型與微變化型。除了降雨上昇雨後緩降正常反應之外，紅菜坪地滑區崩積層與岩盤交界面孔隙水壓會因降雨而發生孔隙水壓突然下降之異常反應。根據地表與地下位移觀測資料，推測此一降雨-孔隙壓力變化複雜之行為與崩積層受剪體積變化造成之超額孔隙壓力變化有關，降雨-孔隙壓力上升-變形-孔隙壓力下降之特性為紅菜坪地滑地為緩慢潛移的可能解釋。另外，本研究根據雨場分割結果，探討降雨特性與降雨-孔隙水壓異常反應之關聯性，結果發現當累積雨量超過150~200mm、降雨延時超過11hr 以及降雨強度超過20mm/hr 時，紅菜坪地區崩積層與岩盤交界面即可能產生驟降之異常反應。

The Hungtsaiping Landslide triggered by Chi-Chi earthquake covers an area of hundreds of hectors. The rock mass is covered by a thick colluvial that is as deep as 82m. To explore the sliding mechanisms, GPS, inclinometer and fiber optic displacement and water pressure sensing systems were used to monitor the status of the landslide.
Among them, three piezometers installed in the interface of colluvial and bed rock automatically recorded lots of valuable data during July of 2005 to the end of 2006. Based on records of the pore pressure varied with rainfall, normal and abnormal responses were identified and
discussed. The seasonal variation of pore pressure was less than 30 kPa. During the period of heavy rainfall, the variation of pore pressure was less than 5 kPa. Besides the normal response of pore pressure increased quickly after rainfall, abnormal response was observed which the pore pressure decreased during the period of heavy rainfall. In the same period of the pore pressure dropped suddenly, the surface and subsurface displacement was also observed. Accordingly, the decreasing of pore pressure could original from the dilation in the sliding surface which induced a negative excess pore pressure. The
process of “rainfall - infiltration - water level raising – sliding – negative excess pore pressure develop” can be used to account for the the creep mechanism of Hungtsaiping Landslide.

1.Abramson, L.W., Lee, T.S., Sharma, S., and Boyce, G. M., 1996. Slope
stability and stabilization methods, John Wiley & Sons, Inc., New York, 629p.
2.Anderson, S.A., and Sitar, N., 1995. Analysis of rainfall induced debris flow,
Journal of Geotechnical Engineering, ASCE, 121(7):544-552.
3.Brand, E.W., 1981. Some thoughts on rainfall induced slope failures,
Proceeding of 10thInternational Conference on Soil Mechanics and
Foundation Engineering, pp.373-376.
4.Brenner, R.P., Tam, H.K., and Brand, E.W., 1985. Field stress path simulation
of rain induced slope failure, Proceedings of 11th International Conference on
Soil Mechanics and Foundation Engineering, 2:373-376.
5.Collins, B.D., and Znidarcic, D., 2004. Stability analysis of rainfall induced
landslides, Journal of Geotechnical and Geoenvironmental Engineering,
ASCE, 130(4):362-372.
6.GEO, 1984. Geotechnical manual for slope, Geotechnical Engineering Office,
Civil Engineering Department, second edition, Hong Kong, 300p.
7.Iverson, R.M., 2005. Regulation of landslide motion by dilatancy and pore
pressure feedback, Journal of Geophysical Research, Vol. 110, F02015,
doi:10.1029 /2004JF000268 .
8.Iverson, R.M., 2000. Landslide triggering by rain infiltration, Water Resources
Research, 36(7):1897-1910.
9.Lumb, P., 1975. Slop failures in Hong Kong, Quarterly Journal of Engineering
Geology, 8:31-65.
10.Salciarini, D., Godt, J.W., Savage, W.Z., Conversini P., Baum R.L., and
Michael J.A., 2006. Modeling regional initiation of rainfall induced shallow
landslides in the eastern Umbria Region of central Italy, Landslides,
3:181-194.
11.Sidle, R.C., and Swanston, D.N., 1982. Analysis of a Small debris slide in
coastal alaska, Canadian Geotechnical Journal, 19:167-174.
12.Sitar, N., Anderson, S.A., and Johnson, K.A., 1992. Conditions leading to the
initiation of rainfall induced debris flow, Geotech. Eng. Div. Specialty Conf.:
Stability and Perf. of Slopes and Embankments-II. ASCE, New York, pp.
834-839.
13.Takahashi, T., 1981. Estimation of Potential debris flows and their hazardous
zones, Journal of Natural Disaster Science, 3(1): 57-89.
14.Terzaghi, K., 1950. Mechanism of landslides, In: Paige, S. (Ed.), Application
of Geology to Engineering Practice (Berkey Volume), Geological Society of
America, New Your, pp.83-123.
15.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.
16.Wei, C.Y. and Lee, J.F., 2006. The application of digital aerial photography in
74
the study of hungtsaiping landslide, Chungliao, Nantou County, Bulletin of
the Central Geological Survey, 19:39-59.
17.Wieczorek, G.F., 1987. Effect of rainfall intensity and duration on debris
flows in central santa cruz Mountains, California, Flows/ Avalanches: Process,
Recognition and Mitigation, Geological Society of America, Reviews in
Engineering Geology, 7:93-104.
18.Wilson, R. C., 1997. Normalizing rainfall/debris-flow thresholds along U. S.
Pacific coast for long-term variation in precipitation climate, Proceedings of
the First International Conference on Debris-Flow Hazards Mitigation,
pp.32-43.
19.工業技術研究院能源與資源研究所，1993。梨山地區地層滑動調查與整
治方案規劃總報告，台灣省政府農林廳水土保持局。
20.何春蓀，1955。南投集集大山煤田地質地形圖及構造剖面圖，經濟部中
央地質調查所。
21.青木佑久，1980。過去に土石流災害等の災害なまらした降雨特徵，土
木技術資料，Vol.22-2，pp.71-76。
22.青山工程顧問有限公司，2006。台18 線28.9K~31.5K (五彎仔)地滑區調
查、整治規劃及安全評估，交通部公路總局第五區養護工程處委辦計畫
第三次總結報告，交通部公路總局。
23.李汴軍、許蕙蘭、曹舜評，2005。大崙山區地下水位與降雨關係之初步
分析，第十一屆大地工程研討會，第I14-1-I14-4 頁。
24.李明熹，2006。土石流發生降雨警戒分析及其應用，國立成功大學水利
及海洋工程研究所博士論文。
25.李錦發、魏正岳、林明旻與黃健政，2004。數值航測應用於山崩調查-
以紅菜坪地滑為例，經濟部地質調查所。
26.李旺儒，2006。比較集集地震引致紅菜坪地滑及九份二山地滑特性之研
究，國立中央大學應用地質研究所碩士論文。
27.交通部中央氣象局地震測報，http://www.cwb.gov.tw/。
28.黃立煌，1985。崩積土邊坡水壓計資料分析，地工技術，第12 期，p26-34。
29.黃安斌、林慶偉、林銘郎、董家鈞，2005。紅菜坪地滑監測系統建立與
75
變形機制研究(1/2)，經濟部中央地質調查所報告。
30.黃安斌、林慶偉、林銘郎、董家鈞，2006。紅菜坪地滑監測系統建立與
變形機制研究(2/2)，經濟部中央地質調查所報告。
31.柯虹如，2006。紅菜坪崩積層特性與地滑行為初探，國立台灣大學土木
工程研究所碩士論文。
32.財團法人中華顧問工程司，1999。85 年度坡地災害整治計畫梨山地區地
層滑動基本設計與補充調查委託技術服務成果報告，台灣省政府農林廳
水土保持局第二工程所。
33.富國技術工程公司，2001。梨山地滑區第四期監測系統，委託技術服務
工作報告。
34.國立成功大學防災研究中心，1998。地質危險區公路及河川橋樑之維護
管理與防救災對策之研擬-以台十一線及台二十一線為例期末研究報告，
台灣省交通處公路局。
35.曾佳漢，2006。應用質點影像測速技術分析集集地震於台灣中部所引發
之非遽變山崩國立台灣大學地質科學研究所碩士論文。
36.鄧鳳儀，2005。地滑地區滲流及地下排水工法對邊坡穩定影響之數值模
擬-以梨山地滑區為例，國立中興大學水土保持學系碩士論文。
37.謝宗霈，2007。應用影像計算於地表變位之監測-以紅菜坪地滑為例，國
立成功大學地球科學研究所碩士論文。