以降雨引發地下水位變化探討宜蘭縣南澳鄉東澳嶺之崩塌潛勢

To study the collapse potential at Dongao Ridge, Nanao Township, Yilan County by groundwater level variation under heavy rainfall

陳弘達(Hung-Ta Chen)；唐琦(Chi Tang)

地下水位 ； 崩塌潛勢 ； Groundwater level ； Collapse potential

水保技術

第18卷第1、2期（2024 / 06 / 01）

22 - 31

繁體中文;英文

宜蘭縣南澳鄉東澳嶺附近蘇花公路115K+900m路段，於2010至2012年期間因暴雨有引發道路邊坡崩塌災情，當經治理工程完成後，即於2015年期間就崩塌跡地建置邊坡崩塌監測系統，故本研究針對該年期間有因颱風、季風所引起豪雨事件時之地層傾斜及地下水位變化進行研判與分析，以期確認淺層崩塌發生潛勢。研究結果可知：宜蘭縣南澳鄉東澳嶺崩塌地於大降雨後會造成崩塌跡地上側區域之地下水位上升幅度約為20m，崩塌跡地於出現蝕溝區位，受地層含水量偏高影響，會在大降雨後之地下水位上升幅度約為2至3m，崩塌跡地於不易透水區位之地層多呈現穩定狀態，而本崩塌跡地於地表下約10m、20m及30m處均有出現滑動面，使其因降雨而誘發淺層崩塌潛勢。

The Landslide disaster happened duration 2010 to 2012 at 115K+900 m road section of Suhua Highway, Dongao Ridge, Nanao Township, Yilan County. After restoration and renovation project had implement on 2015, and then monitoring system be set on side slope .This study focus on heavy rain by typhoon and monsoon that had resulted tilted stratum and groundwater level change, through analysis and judges could helpful for realizing the shallow collapse potential. The results had summarized as follow, after heavy rain by typhoon and monsoon would raise the groundwater level about to 20 m at upper area of landslide slope, meanwhile the soil moisture content of erosion gully could keep in higher state and then raise the groundwater level about to 2-3 m. The impermeable layer appeared in landslide slope would be in a stable status for groundwater level. During heavy rain could lead the sliding surface within 10, 20 and 30 m under ground of landslide area, and shallow collapse potential could be happen.