Journal of the Korean Geotechnical Society (한국지반공학회논문집)

Korean Geotechnical Society (한국지반공학회)
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Estimation on Unsaturated Characteristic Curves of Tailings obtained from Waste Dump of Imgi Mine in Busan

부산 임기광산 폐석적치장 광미의 불포화 특성곡선 산정

  • Song, Young-Suk (Geologic Environment Division, Korea Institute of Geoscience and Mineral Resources) ;
  • Kim, Kyeong-Su (Geologic Environment Division, Korea Institute of Geoscience and Mineral Resources) ;
  • Jeong, Sueng-Won (Geologic Environment Division, Korea Institute of Geoscience and Mineral Resources) ;
  • Lee, Choon-Oh (Geologic Environment Division, Korea Institute of Geoscience and Mineral Resources)
  • 송영석 (한국지질자원연구원 지구환경연구본부) ;
  • 김경수 (한국지질자원연구원 지구환경연구본부) ;
  • 정승원 (한국지질자원연구원 지구환경연구본부) ;
  • 이춘오 (한국지질자원연구원 지구환경연구본부)
  • Received : 2014.01.29
  • Accepted : 2014.03.13
  • Published : 2014.03.31
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Abstract

To investigate the unsaturated characteristics of the tailings obtained from the waste dump at Imgi mine, matric suction and volumetric water content were measured in both drying and wetting processes using Automated Soil-Water Characteristics Curve Apparatus. Based on the measured result, Soil Water Characteristic Curves (SWCC) were estimated by van Genuchten model. According to the unsaturated soil classification method, the tailings of the waste dump correspond to clayey sand. As a result of Suction Stress Characteristic Curve (SSCC) by Lu and Likos model, SSCC has a shape of S which is similar to SWCC. The hysteresis phenomenon occurred in SSCCs, which means the suction stress of drying path is larger than that of wetting path in the same effective degree of saturation. The effective stress of unsaturated soil is equal to that of saturated soil when matric suction is less than Air Entry Value (AEV). However, the effective stress of unsaturated soil is larger than that of saturated soil when matic suction is more than AEV. Meanwhile, unsaturated hydraulic conductivity by van Genuchten model decreased with increasing matric suction, and the hydraulic conductivity of drying path is larger than that of wetting path.

본 연구에서는 임기광산 폐석적치장을 형성하고 있는 광미의 불포화 특성을 조사하기 위하여 자동 흙-함수특성곡선(SWCC) 측정장치를 이용하여 건조 및 습윤과정에 따른 모관흡수력과 체적함수비를 측정하였다. 측정결과를 토대로 van Genuchten 방법을 이용하여 흙-함수특성곡선(SWCC)을 산정하였다. 산정된 흙-함수특선곡선(SWCC)의 ${\alpha}$와 n을 이용하여 흙의 종류를 구분하면 폐석적치장 광미시료는 점토질 모래(clayey sand)에 해당한다. Lu and Likos 방법으로 광미시료의 흡입응력특성곡선(SSCC)을 산정한 결과 흙-함수특성곡선(SWCC)과 유사한 S자형 곡선을 나타낸다. 동일한 유효포화도에서 건조과정의 흡입응력이 습윤과정의 흡입응력보다 크게 발생되는 이력현상이 나타났다. 그리고 불포화토의 유효응력은 공기함입치 이내로 작용할 경우 포화시 유효응력과 동일하나, 공기함입치 이상의 모관흡수력이 작용할 경우 포화토의 유효응력보다 큰 값을 갖는다. 한편, van Genuchten 방법으로 산정된 광미시료의 불포화 투수계수는 모관흡수력이 증가함에 따라 감소하며, 건조과정의 투수계수가 습윤과정의 투수계수보가 크게 발생됨을 알 수 있다.

Keywords

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