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저수지 전기비저항 모니터링에서의 온도효과

Temperature Effects in the Resistivity Monitoring at Embankment Dams

  • Kim, Eun-Mi (Division of Geology and Geophysics, Kangwon National University) ;
  • Cho, In-Ky (Division of Geology and Geophysics, Kangwon National University) ;
  • Kim, Ki-Seog (Heesong Geotek Co., Ltd.) ;
  • Yong, Hwan-Ho (Korea Rural Community Corporation)
  • 투고 : 2018.01.22
  • 심사 : 2018.02.26
  • 발행 : 2018.05.31

초록

저수지 안전진단을 위하여 수행되는 전기비저항 모니터링 자료는 대기의 온도에 영향을 받는다. 특히 국내와 같이 사계절의 온도 변화가 큰 환경에서는 지중온도 변화에 의한 전기비저항의 변화를 무시하기 어렵다. 따라서 온도효과는 전기비저항 모니터링 자료의 정밀한 해석을 어렵게 한다. 이 연구에서는 저수지에서 획득된 다점온도 모니터링 자료를 분석하여 시공간적 지중온도를 추정하고, 이를 이용하여 역산 결과 얻어진 지하 전기비저항 모델에 대하여 온도보정을 수행하였다. 온도보정 결과, 계절변화에 의한 온도 효과는 주로 상부에 국한되며, 심부에서는 무시할 수 있는 것으로 해석되었다. 그러나 댐 제체의 온도 분포만을 가지고 온도 보정을 수행하면 그 효과를 완전히 제거할 수 없다. 이 문제를 극복하기 위해, 저수지 물의 온도 변화에 의한 효과는 대기온도 변화도 함께 포함되어야 할 것으로 보인다.

Resistivity monitoring data at embankment dams are affected by the seasonal temperature variation. Especially when the seasonal temperature variation is large like Korea, the temperature effects may not be ignored in the longterm resistivity monitoring. Therefore, temperature effects can make it difficult to accurately interpret the resistivity monitoring data. In this study, through analyzing the time series of ground temperature collected at an embankment dam, ground temperature variations are calculated approximately. Then, based on the calculated temperature profile with depth, the inverted resistivity model of the embankment dam is corrected to remove the temperature effects. From these corrections, it was confirmed that the temperature effects are significant in the upper, superficial part of the dam, but can be ignored at depth. However, temperature correction based only on the temperature distribution in the dam body cannot remove the temperature effect thoroughly. To overcome this problem, the effect of temperature variation in the reservoir water seems to be incorporated together with the air temperature variation.

키워드

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