六龜紅水仙地區土石流災害之調查、模擬與重建成效

Debris flow hazard investigation,simulation, and recovery effectiveness of Hongshueisian Region,Liugui Township

簡榮興(Jung-Sing Chien)

指導教授 ： 施邦築

國立臺北科技大學/工程學院/土木與防災研究所/碩士(2013年)

https://doi.org/10.6841/NTUT.2013.00496

摘要

六龜紅水仙地區於民國98年莫拉克颱風，發生大規模土砂災害。故本研究以農委會水土保持局所列管之高市DF055土石流潛勢溪流(紅水仙溪)為探討案例，本研究區域自民國97~101年進行多次土石流之易致災因子調查，利用3S技術(GPS、GIS、RS)及UAV無人航空載具拍攝，探討近年來集水區崩塌地、土石流與河道變化。而針對崩塌料源區部份，採用赤平投影分析法，應用在不連續面調查，以探討大規模崩塌之破壞機制。並根據現勘結果進行50年及200年雨量重現期之FLO-2D二維數值模擬，分析土石流流動特性與災害範圍比對。最後，本研究尚探討災後緊急搶修之原則、流程與策略，並在原址重建紅水仙橋，其災後重建之成功案例，可供相關單位作為平時之災害搶修與復建教育推廣之參考。本研究結果如下：
(1)由災前災後土石流調查結果，堆積區土砂高度約2~4m，堆積扇範圍17.27公頃，最寬處達610m，中間寬約350m，估計現有之土方量約為60萬m3；而流動區兩岸溪谷坡面遭土石流縱、橫向破壞，河寬約20m；發生區之崩塌總面積約為13.14公頃，崩塌深度約介於5~15m之間，預估總崩塌之土方量約有130萬m3以上；(2)透過地表地質調查結果，可以求得一組平均之不連續面位態為N60°E/60°E。於中游流動段兩岸坡面岩體受岩層之褶皺或破碎，致層面等規則性不連續面對坡面之發育，產生大量破碎帶地層；上游發生區岩層節理發達、連續性佳，為層面及坡面岩楔解壓節理所形成之楔型滑動；(3)由200年重現期FLO-2D模擬堆積範圍約10.71ha，而風災實際造成紅水仙地區之堆積扇範圍為17.27公頃，兩者之差異範圍約為6.56公頃，約有38%之差異。

關鍵字

3S ； UAV ； 赤平投影法 ； FLO-2D ； 災後重建

並列摘要

Typhoon Morakot caused several landslides, which triggered a severe debris flow at Hongshueisian torrent, Liugui Township in 2009. This case study focused on the landslide and debris flow event in Kaohsiung DF055 potential debris flow torrent (Hongshueisian torrent).
The Hongshueisian watershed had been investigated with 3S techniques (GPS, GIS, RS) and images taken by Unmanned Aerial Vehicle (UAV) between 2008 and 2012 to discussthe changes of landslide, debris flow and river channel in the watershed. Stereographic projection method was applied to investigate the initial area of debris flow to discuss the failure mechanism of landslides. Finally FLO-2D was applied for numerical simulation to compare the difference between hazard area and simulation results (50 and 200 years return period). This study also discusses the post-hazard emergency reconstruction principle and procedure, and considers the reconstruction of Hongshueisian Bridge, which was completed in the end of 2012, to be a successful case, and could be an example for emergency reconstruction and education use in the future.
The results of this study are as follow：
1. Compare the investigation result before and after Typhoon Morakot shows that the inundation area is 17.27 ha, width of the depostion fan ranges from 350m (middle) to 610m (bottom of fan), with deposition depth between 2 to 4m. The estimated deposition volume is greater than 600,000m3. The channel width in transportation area is 20m, the channel shows evidence of degradation and bank erosion. The landslide area in the initial area is 13.14 ha, and with 5 to 15m landslide depth, around 1,300,000m3 of debris was washed down.
2. From the result of field geology investigation, can obtain mean of discontinuities attitude is N60°E/60°E. The banks of transportation area were affected by fold structures and discountinuity with lots of fragments. The slopes in the initial area were full of well development joints, the great continuity contributes to the forming of wedge slides in the watershed.
3. The numerical simulation of FLO-2D with 200 years return period rainfall data shows 10.71 ha of inumdation area, which is 6.56 ha less (38% less) compare with the 17.27 ha during Typhoon Morakot.

並列關鍵字

3S ； UAV ； Stereographic projection ； FLO-2D ； Disaster reconstruction

參考文獻

43. 趙啟宏，土石流之數值模擬及流變參數特性之探討，碩士論文，國立臺灣大學土木工程學研究所，台北，2004。

19. 沈哲緯、曹鼎志、鄭錦桐、王天佑、陳頎夫，「以3S技術進行屏東縣霧台鄉好茶村土砂災害調查與評估」，中興工程季刊，第102期，2009，第27-35頁。

18. 楊明德、蘇東青、楊曄芬 ，「草嶺地區土石流潛勢調查與評估」，中華水土保持學報，第36(3)期，2005，第301-312頁。

23. 溫振宇，結合地震與颱風因子之山崩模式分析，碩士論文，國立成功大學地球科學研究所，台南，2005。

35. 林暘壹、詹錢登、郭峰豪，「角埔溪土石流流動模擬研究」，中華防災學刊，第5期，2013，第51-61頁。