대한토목학회논문집 (KSCE Journal of Civil and Environmental Engineering Research)

  • 제42권2호
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  • Pages.181-186
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  • 2022
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  • 1015-6348(pISSN)
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  • 2799-9629(eISSN)
대한토목학회 (Korean Society of Civil Engeneers)
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댐체 강화 RIM부 그라우팅을 위한 지반상태 기준 결정

Determining of Ground Condition Criteria for Dam Reinforced RIM Grouting

  • 한기승 ((주)월드이앤씨) ;
  • 이동혁 (한양대학교 건설환경공학과) ;
  • 박두희 (한양대학교 건설환경공학과)
  • 투고 : 2022.03.03
  • 심사 : 2022.03.23
  • 발행 : 2022.04.01
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초록

댐체 구조물 사면부(RIM부)는 본체와 원지반이 접속하는 매우 중요한 접촉부(interface) 이다. 일반적으로 댐 구조물 사면부 지반보강을 위한 그라우팅 설계시 제한된 자료(시추공, 지질도 등)를 이용하여 계획하기 때문에 사면부 RIM 그라우팅 대상 원지반 특성을 정확하게 고려하여 설계하기는 매우 어려운 실정이다. 또한, 실제 차수성이 확보된 원지반에 설계시 계획된 그라우팅 물량을 천공 주입할 경우에는 차수성이 확보된 원지반이 교란되어 차수효과를 오히려 저해할 가능성도 있다. 이를 극복하기 위해서는 구조물 사면부(RIM) 그라우팅 수행 전에 지질여건을 우선적으로 고려하고 현장수리시험을 통하여 원지반에 대한 최적의 그라우팅을 실시여부를 결정하는 것이 기초처리 대상 지반의 차수성 확보에 매우 적합하다고 판단된다. 본 논문에 적용된 RIM부 그라우팅 판단여부를 결정하기 위하여 대상 구간의 사면구간 암반에 대하여, 파일럿 홀(Pilot hole) 수압시험 수행 분석결과 1 Lugeon 이하의 차수성을 나타내며, 시멘트 주입량 역시 1 kg/m 이하의 주입결과를 나타낸다. 이때는 그라우팅을 실시하는 것이 오히려 역효과가 난다고 판단된다. 이 시험결과 수치는 사면 절취시 육안관찰과 지질도 작성결과를 이용하여 분석할 때 댐 설계 기준인 1 Lugeon 이하의 경우가 되어, 괴상(Massive)의 차수성이 어느 정도 확보된 암반으로 평가할 수 있다. 따라서 댐체 구조물 사면부에 RIM 그라우팅의 실시 결정기준은 암반상태에서 1 Lugeon 차수성이고, 시멘트 주입량 역시 1 kg/m을 기준으로 하여 RIM 그라우팅 실시여부를 결정하는 것이 바람직하다고 판단된다.

Dam slope RIM is a highly important contact interface where the main body and the base surface are connected. In general, when the grouting for the slope of the dam structure is designed, it is planned using limited data (drilling, geological map, etc.). This makes it very difficult to accurately consider the original ground characteristics of the slope RIM grouting target, In addition, when the grouting volume planned during the design is drilled and injected into the original ground where the waterstop is secured, there is a possibility that the original ground with the waterstop is disturbed and the effect of the waterstop is rather diminished. In order to overcome such problems, it is more suitable to first consider geological conditions and determine whether to perform optimal grouting on the original ground through on-site repair tests before performing RIM grouting. In this paper, to determine the grouting of the RIM unit, a pilot hole water pressure test was performed on the rock of the slope in the target section. The analysis shows grouting volume of 1 Lugeon or less, and the cement injection amount also shows the injection result of 1 kg/m or less. In this case, performing grouting is rather counterproductive. This result can be evaluated through a rock of which some degree of order of mass is secured, as it is a dam design standard of 1 Lugeon or less when analyzed, using the results of visual observation and geological map creation during slope cutting. Therefore, in conclusion, it is preferable to make the decision for using RIM grouting on the slope of the dam body structure, based on 1 Lugeon in a rock state, and the cement injection amount also at 1 kg/m.

키워드

참고문헌

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