羅浮合流部落土石流之致災機制分析與數值模擬

桃園市復興區羅浮里合流部落集水區，於2015 年8 月8 日蘇迪勒颱風期間因強降雨誘發邊坡岩屑崩滑形成土石流，造成下游 15 戶民宅遭到破壞或淤埋。本研究以遙測影像、UAV 攝影測量、致災雨量分析、微地形判釋、崩塌地倒樹線型、現地勘查及數值模擬探討土石流致災機制與災害成因。合流集水區上游為一舊岩體滑動區，且存在古土石流堆積扇地貌，本案例災害主要受降雨形成之地表逕流沖刷，導致坡腳失穩之後退式岩屑崩滑。本文採RAMMS 數值模擬以參數逆推法探尋土石流發生之可能情境，並與災後地貌進行驗證。災害動態影片分析與數值模擬驗證則顯示合流部落土石流之流動段流速約14.3 m/s，受災堆積段之溢淹深度則介於1-5 m。

關鍵字

蘇迪勒颱風；土石流；岩屑崩滑；倒樹線型； RAMMS

並列摘要

Typhoon Soudelor brought abundant rainfall in northern Taiwan on August 8, 2015. The rainfall caused a shallow landslide which was transformed instantly into a debris flow disaster in the Heliu catchment. We integrate remote sensing, rainfall analysis, micro-topography interpretation, lineament of tree fall, field investigation, a UAV survey, and RAMMS simulation to explore the failure mechanism and flow dynamics of this rainfall-induced debris flow. The high resolution shading relief map depicts the landforms of both the old deep-seated landslide and the ancient debris-flow fan. In this study, different numerical scenarios are performed by RAMMS to analyze the possible influence area via adopting the back-analysis approach. In comparison with the post-disaster landform model, the best-fit parameters for Heliu debris flow were also obtained. In addition, verification of dynamic images demonstrates that the maximum flow velocities for the event and deposition height on the debris-flow fan are about 14.3 m/s and 1-5 m, respectively.

並列關鍵字

Typhoon Soudelor ； debris flow ； debris slide ； lineament of trees fall ； RAMMS

國際替代計量

羅浮合流部落土石流之致災機制分析與數值模擬

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