電阻剖面影像法於壩體滲漏調查之應用

Application of ERT to Leakage Investigation in Dams

林志平(Chih-Ping Lin) ； 洪瑛鈞(Yin-Chun Hung) ； 尤仁弘(Zen-Hung Yu) ； 鄒和瀚(He-Han Zou)

《先進工程學刊》 3卷1期 (2008/01) Pp. 49-55

https://doi.org/10.29948/JAE.200801.0007

摘要

水庫常因庫龄增加、壩體材料老化或受地震的影響，致使水庫壩體產生滲漏問題，影響水庫之功能與安全性。目前除了表面目視檢查，並沒有有效的方法可以檢測壩體內部之滲漏情形，本文介紹電阻剖面影像法於壩體滲漏調查之應用，藉由不同位置與間距之電極排列探測不同位置與影響深度之視電阻值，再透過反算所得到的二維電阻剖面影像，可初步判斷壩體是否有潛在滲漏之區域及其分佈情形。在混凝土結構物上之施測方面，為不破壞混凝土之完整性，本研究克服傳統不銹鋼電極棒需貫入受測材料施測之缺點，採用新式非侵入式平鈑電極進行電阻探測。本文案例研究之場址包括新山水庫之土石壩體及石門水庫混凝土廊道，結果顯示電阻剖面影像法在偵測試驗場址潛在滲漏區域有相當顯著之成果，除可顯示壩體入滲之情形，混凝土施工縫存在之區域在電阻剖面影像上亦有明顯呈現。

關鍵字

地電阻率 ； 地電阻影像探測 ； 水庫滲漏

並列摘要

The reservoir structures deteriorate with time and may be damaged during earthquakes. Current evaluation of dam safety relies primarily on visual inspection. There is a great demand for effective non-destructive methods to examine the interior of the dam. This study was aimed at assessing the performance of electrical resistivity tomography (ERT) applied to the investigation of dam leakage. ERT measurements were carried out on the dam surface with an electrode array to obtain the apparent-resistivity profile, and used the inversion technique to estimate the resistivity profile. The resistivity profile was then used to detect and locate potential leakage in a dam. Current ERT measurements use destructive metal rods as electrodes, which are not desirable for concrete structures. A non-penetrative electrode was developed and evaluated for measurements in concrete structures. Two case studies were conducted at the Shin-Shan earth-fill dam and the Shih-Man Reservoir. The case studies show remarkable effect of ERT for leakage investigation. It is also possible to detect cracks in concrete structures.

並列關鍵字

electrical resistivity ； electrical resistivity tomography ERT ； dam leakage