• 제목/요약/키워드: Concrete-Faced Rock-fill Dam (CFRD)

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불리한 조건에서의 콘크리트 표면차수벽형 석괴댐 설계 및 시공 (Study on Design and Construction of CFRD under Unfavorable Conditions)

  • 박동순;김형수
    • 지질공학
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    • 제16권1호
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    • pp.97-107
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    • 2006
  • 콘크리트 표면차수벽형 석괴댐(CFRD; Concrete Faced Rockfill Dam)는 기존의 중심코어 형 락필댐(ECRD; Earth Cored Rockfill Dam)과 대별되는 우수한 구조적, 재료적 특성으로 현재 가장 널리 활용되는 댐 형식이다. 본 고에서는 불리한 조건에서의 CFRD의 설계와 시공에 있어 최근에 부각된 최신 기술들을 정리하여 향후 활용에 도움을 줄 수 있도록 하였다. 예를 들어, 연약한 암을 이용한 댐체 축조, sand-gravel fill, 연결 슬래브 공법, 충적층 기초의 처리 공법등에 대한 간략한 기술적 동향을 고찰하여 관련 기술자들의 이해를 돕고자 하였다.

Stability analysis on the concrete slab of the highest concrete-faced rock-fill dam in South Korea

  • Baak, Seung-Hyung;Cho, Gye-Chun;Song, Ki-Il
    • Geomechanics and Engineering
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    • 제13권5호
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    • pp.881-892
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    • 2017
  • Design and management of concrete slabs in concrete-faced rock-fill dams are crucial issues for stability and overall dam safety since cracks in the concrete face induced by stress, shrinkage, and deterioration can cause severe leakage from the reservoir into the dam. Especially, the increase of dam height to a certain level to enhance the storage capacity and to improve hydraulic stability can lead to undesirable deformation behavior and stress distribution in the existing dam body and in the concrete slabs. In such conditions, simulation of a concrete slab with a numerical method should involve the use of an interface element because the behavior of the concrete slab does not follow the behavior of the dam body when the dam body settles due to the increase of dam height. However, the interfacial properties between the dam body and the concrete slab have yet to be clearly defined. In this study, construction sequence of a 125 m high CFRD in South Korea is simulated with commercial FDM software. The proper interfacial properties of the concrete slab are estimated based on a comparison to monitored vertical displacement history obtained from the concrete slab. Possibility of shear strength failure under the critical condition is investigated based on the simplified model. Results present the significance of the interfacial properties of the concrete slab.

모형실험에 의한 콘크리트 표면차수벽형 석괴댐의 주응력비 특성 분석 (Characteristics Analysis of Principal Stress Ratio in Concrete Faced Rockfill Dam Using a Model Test)

  • 김용성
    • 한국농공학회논문집
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    • 제48권4호
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    • pp.33-40
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    • 2006
  • In present study, the principal stress condition needed to conduct cubical large-scale triaxial test which can reflect three dimensional stress condition (or plain strain condition) in a dam was investigated by performing model test and numerical analysis and the principal stress ratio varying with the height of CFRD was examined. Also, the principal stress ratio in CFRD body was investigated from the monitoring results of horizontal and vertical earth pressure gages, installed in the center zone and lower part of transition zone of the dam body, respectively, in order to consider the principal stress condition in the large-scale triaxial test to model the behavior of CFRD. The result of the study indicated that the principal stress ratio decreased gradually from the lower to the upper part in the dam body for its center axis and was about 0.5 and 0.2 in the lower and upper part, respectively.

CFRD의 최근 설계ㆍ시공기술 동향 (Recent Techniques for Design and Construction of CFRD)

  • 박동순;김형수;임정열
    • 지질공학
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    • 제15권1호
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    • pp.77-86
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    • 2005
  • CFRD(Concrete fared Rockfill Dam)는 기존의 중심코어형 락필댐과 대별되는 우수한 구조적, 재료적 특성으로 현재 가장 널리 활용되는 댐 형식이다. 본 고에서는 그동안 이루어져온 기술의 축적을 바탕으로 CFRD의 설계와 시공에 있어 최근에 부각된 최신 기술들을 정리하여 향후 활용에 도움을 줄 수 있도록 하였다. 특별히 본 고에서는 최근 경험을 바탕으로 실무에서 적용되고 있는 연약한 암을 이용한 댐체 축조 사례, 대단히 큰 입경의 락필 재 대신 도입된 sand-gravel fill 댐에 대한 경험, plinth와face slab를 연결하기 위해 새롭게 채택된 연결 슬래브공법, 기존 댐의 증고사례, 역침투 현상, 댐 하류의 환경친화죤, 차수벽 슬래브의 두께와 철근비의 변화 추이, 충적층 기초의 처리, 최근 적용되기 시작한 curb element 공법등에 대한 간략한 기술적 동향을 고찰하여 관련 기술자들의 이해를 돕고자 하였다.

Framework for Estimating Appropriate Construction Duration of CFRD in the Planning Phase

  • Kim, In Kyum;Kim, Kyong Ju;Yun, Won Gun
    • 국제학술발표논문집
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    • The 6th International Conference on Construction Engineering and Project Management
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    • pp.604-605
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    • 2015
  • To secure quality of dam construction needs appropriate construction duration. Tight construction schedule may have negative influence on infrastructure quality, work safety and maintenance cost. It is necessary to reflect proper construction duration in the planning phase. There have been standards for estimating construction duration of building and industrial complex development but dam construction have not. In order to estimate construction duration of CFRD, feasible study reports and design reports were analyzed to acquire available information. After that, considering on construction duration methods such as comparison with similar cases, approximate estimating formula, approximate quantity assumption were adapted to Critical Path items. Hence, this study present framework for construction duration estimating of CFRD in the planning phase. This framework can be applied other types of dam along the same line.

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표면차수벽형사력댐의 침투거동에 관한 연구 (Study on Seepage Behavior of Concrete Faced Gravel-Fill Dam)

  • 조성은;김기영;박한규;하익수
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2008년도 추계 학술발표회
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    • pp.836-841
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    • 2008
  • CFRD (Concrete Faced Rockfill Dam) has been world-widely constructed due to a lot of advantages compared with rockfill dam and recently, sand/gravel materials, instead of crushed rock materials, are also utilized as a main rockfill material to overcome geological and environmental problems. In this paper, the process of water infiltration into the originally unsaturated sand/gravel-fill dam is studied using two-dimensional saturated-unsaturated seepage theory. According to the results of seepage analysis, if the effective drainage zone is installed in the dam, the reservoir water infiltrate into the dam along a downward flow path towards the lower drainage area. The main body constructed with sand/gravel materials, therefore, remains unsaturated.

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CFRD의 담수 후 정부침하량 예측 (Crest Settlement Prediction of Concrete Faced Rock-Fill Dam After Initial Impounding)

  • 김용성;박한규;임희대
    • 한국농공학회:학술대회논문집
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    • 한국농공학회 2005년도 학술발표논문집
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    • pp.349-354
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    • 2005
  • In this study, settlement characteristics of 23 CFRD was investigated from monitoring data and the method to estimate the crest settlements considering internal settlement during constructions was proposed. Moreover, crest settlement smaller than 20cm and deflection of face slab smaller than 20cm are not considered to be critical to the stability of large dam whose height is over 40m. Therefore, we assigned the region as safe zone that can be used as a guideline of maintenance of dam. These estimated data can be used in the design, construction and long-term maintenance in domestic CFRD hereafter.

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차수벽에 균열이 발생한 표면차수벽형사력댐의 침투거동 연구 (Study on Seepage Behavior of Concrete Faced Gravel-Fill Dam with Cracked Face Slab)

  • 조성은;박한규;임은상;김기영
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2009년도 춘계 학술발표회
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    • pp.866-873
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    • 2009
  • CFRD (Concrete Faced Rockfill Dam) has been world-widely constructed due to a lot of advantages compared with rockfill dam and recently, sand/gravel materials, instead of crushed rock materials, are also utilized as a main rockfill material to overcome geological and environmental problems. In this paper, the process of water infiltration into the originally unsaturated sand/gravel-fill dam is studied using two-dimensional saturated-unsaturated seepage theory. According to the results of seepage analysis, if the effective drainage zone is installed in the dam, the reservoir water infiltrate into the dam along a downward flow path towards the lower drainage area. The main body constructed with sand/gravel materials, therefore, remains unsaturated.

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CFRD 시공시 축조재료의 다짐특성 평가 (Evaluation of the Compaction Characteristics of CFRD Construction Materials)

  • 한상현;여규권;박종화
    • 지질공학
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    • 제20권4호
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    • pp.415-424
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    • 2010
  • 콘크리트 표면차수벽형 석괴댐에서 Zone별 거동특성을 평가하기 위하여 시험성토를 실시하였다. 본 연구에서는 기존의 시방기준에 제시된 각 Zone에 대한 축조재료 기준을 만족하는 시험재료를 선정하여 포설두께, 전압회수 및 함수비 등을 변경시키면서 다짐성토를 실시하였다. 이때의 시험다짐에 대한 성토체의 침하율, 다짐밀도, 함수비 및 투수계수의 변화를 측정하였다. 시험분석 결과 전압회수와 현장다짐밀도관계, 현장다짐밀도와 침하율의 관계, 다짐회수와 침하율의 관계, 침하율과 포설두께의 상관관계 등을 제시하였다. 특히, 투수계수와 다짐전압회수와의 관계를 제시하였고 이러한 연구를 통하여 효율적인 다짐관리기준을 마련하고자 하였다.