以地電阻影像法探討地滑敏感區電阻率構造與環境因子之關係

山崩事件易受天氣條件（如：豪雨、颱風）觸發，若能在地滑敏感區進行監測，比較降雨前後敏感區的構造改變，便能對山坡地的整治與災害預防提供有益的資訊。本研究於長期處於地滑問題的桃園介壽國中內，布置了一條總長67.5公尺之電極陣列，使用非傳統的交錯排列法，並設定儀器於每日定時進行直流電阻法的測量。分析時間為民國一零三年六月五日至九月二十九日，濾除品質不良的資料，再計算初始資料與監測資料的變化率，可觀察到電阻率隨時間產生的細微變化，並推估雨水在地表下的滲流路徑。接著參考中央氣象局復興測量站的雨量及氣溫資料，探討觀測值、降雨量、溫度之間的關係。本研究結果發現，觀測值會受到過去二十四小時的日降雨量影響，日降雨量大，觀測值便會下降，反之若日降雨量只有數mm或未降雨，觀測值便會回升。再比對觀測值與溫度資料，發現觀測值的改變與溫度的改變並無相關性。接著對照不同時間點的電阻率剖面及其變化率，再比對數值模型與觀測資料的結果，得知雨水入滲的路徑可能在剖面水平座標35公尺至45公尺處。

關鍵字

地電阻法；直流電阻法；地滑敏感區

並列摘要

Because Electrical Resistivity Tomography(ERT) is fast, cheap and accuracy is used to resource exploration and engineering survey, especially disaster prevention. Electrical resistivity survey was carried out continuously for three months to monitor a hazardous hillslope at Jieshou Junior High School in Taoyuan. The monitor site is located at hillslope between the school building and playground. The length of survey line is 67.5 m. The electrode array is alternate array, which is different from traditional array like Wenner array or Dipole-Dipole array. The instrument will measure automatically every day. The study analyzed the data from 2014 June 5 to 2014 September 29. Except ERT profiles of different dates, also calculates the rate of change of resistivity between base model and monitor data, to observe the weak change. Then refer the data from Central Weather Bureau, to discuss the relation between the observed values, rainfall and air temperature. We can observe after heavy rainfall, observed value would decrease, but no obvious change as air temperature change. Through the comparison of inverted sections and rate of change of different time, and comparison of inverted section of real data and synthetic model, we can know the route of infiltration at horizontal coordinate 35 to 45 meters.

並列關鍵字

Direct Current Resistivity Method ； Geoelectric Resistivity Method ； ERT ； ERI

參考文獻

Clark, J. A., & Page, R. (2011). Inexpensive Geophysical Instruments Supporting Groundwater Exploration in Developing Nations. Journal of Water Resource and Protection, Vol.03No.10, 13. doi: 10.4236/jwarp.2011.310087

林澤宗. (2012). 地電法於地下掩埋物調查之研究. (碩士), 國立中央大學, 桃園縣.

Zhang, G., Zhang, G. B., Chen, C. C., Chang, P. Y., Wang, T. P., Yen, H.Y., Dong, J. J., Ni, C. F., Chen, S. C., Chen, C. W., Jia, Z. Y. (2014). Imaging rainfall infiltration processes with the time-lapse electrical resistivity imaging method. Manuscript submitted for publication.

Metwaly, M., El-Qady, G., Massoud, U., El-Kenawy, A., Matsushima, J., & Al-Arifi, N. (2010). Integrated geoelectrical survey for groundwater and shallow subsurface evaluation: case study at Siliyin spring, El-Fayoum, Egypt. International Journal of Earth Sciences, 99(6), 1427-1436. doi: 10.1007/s00531-009-0458-9

Sirieix, C., Fernández Martínez, J. L., Riss, J., & Genelle, F. (2013). Electrical resistivity characterization and defect detection on a geosynthetic clay liner (GCL) on an experimental site. Journal of Applied Geophysics, 90(0), 19-26. doi: http://dx.doi.org/10.1016/j.jappgeo.2012.12.005

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以地電阻影像法探討地滑敏感區電阻率構造與環境因子之關係

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