於諸多現地調查與分析中發現,溪流之土石流現象與其集水區內邊坡或坑溝發生流體化崩塌情況息息相關。因此本研究冀以探討流體化崩塌邊坡與溪流型土石流發生潛勢之關係,發展評估方法。 本研究選定莫拉克風災後已發生溪流型土石流之集水區三處,首先透過GIS進行分析單元劃分,建立集水區內分析單元劃分流程,後以同一匯水出口及分析單元面積大於1.5公頃為基準,篩選分析單元,利用分析單元配合前人文獻中所建立之流體化崩塌潛勢分析模式判別集水區中各邊坡可能發生流體化崩塌之區塊,判別成果與實際邊坡災害比對後,吻合度約為82%。 另建立三處集水區為驗證,一處為已發生溪流型土石流集水區,兩處為未發生溪流型土石流集水區,6處集水區中,從4處已發生及2處未發生集水區中所得到之判別成果,進一步探討,研究結果發現,在單一集水區中,流體化崩塌面積比率達30%以上,該集水區發生溪流型土石流機率較高。
The assessment model of fluidizing landslide was developed in this study since the debris flow was frequently related to the fluidized landslides from gullies or slopes in the catchment. Three debris flow streams which occurred in Typhoon Morakot in Kaoping river basin were studied to develop the assessment model. The process of the analysis unit delineation has established based on the micro topography through the tool of GIS, aero photos, the DEM of morphology, and the field verification. The criterion, the basin area larger than 1.5 hectares with the same outlet of a zero-order basin or slope, was applied to the delineation of analysis unit. A total of 198 analysis units were achieved from three debris flow catchments. Eight factors, including A,B, and C, of discriminant model on fluidizing landslide developed by Yang (2014) was selected in this study. Assessed by discriminant model, three catchments have achieved with 50 potential fluidizing landslide units and 148 slope units. Verified with the 21 real fluidized landslide and 40 general landslide events occurred within three catchments in Typhoon Maroka, the good match rate of 82% was achieved. Three verification catchment, one debris flow event and two no debris flow events, have been also conducted through the same delineation procedure to explore the relationship between the among of potential fluidizing landslides to the occurrence of debris flow of a catchment. After total of 6 catchments study, 4 occurred and 2 did not occurred, found that the high occurrence probability to the catchment as the area ratio of potential fluidizing landslide larger than 30%.