• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2007년 가을학술발표회
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• pp.528-541
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• 2007

To get the possible for management and maintenance, it was analyzed the deformation characteristics, such as crest of embankment and concrete face slab, and leakage of concrete faced rockfill dams (CFRD). There are trends that embankment deformation depends on intact strength used rockfills rather than dam height, deformation normal to concrete face slab during the first reservoir filling is occurred more than 80% of the total deformation in general, and the magnitude and trend of concrete face slab deformation is similar to post-construction crest settlement. The results showed that the range of post-construction crest settlement suggested by Sherard and Cooke (1987), and Clements (1984) had a good agreement in the cases using rockfill with very high intact strength, but it had a trend which underestimated crest settlement in the cases using rockfill with medium to high intact strength. The maximum leakage rate in general was observed during the first reservoir filling and long-term leakage rate was rapidly increased when the dam height exceeds approximately 120m.

• 한국안전학회지
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• 제27권6호
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• pp.133-137
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• 2012

Cracking may be used to help predict the cause of deterioration of concrete, since in many cases characteristic cracking patterns are produced. The purpose of this paper is an analysis of the crack cause occurred in concrete faced rockfill dams. We analyzed the concrete placement methods, cracking pattern, the inspection of crack depth by the ultrasonic pulse velocity method, and the measurement of heat of hydration, environmental condition, and so on. In this study, the crack cause of concrete faced rockfill dam is the wrong method of concrete placement, high temperature difference by cement of heat of hydration and concrete of drying shrinkage.

• Geomechanics and Engineering
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• 제17권2호
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• pp.119-131
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• 2019

Time dependent creep settlements are one of the most important causes of material deteriorations for the huge water structures such as concrete faced rockfill dams (CFRDs). For this reason, performing creep analyses of CFRDs is vital important for monitoring and evaluating of the future and safety of such dams. In this study, it is observed how changes viscoplastic behaviour of a CFR dam depending the time. Ilısu dam that is the longest concrete faced rockfill dam (1775 m) in the world is selected for the three dimensional (3D) analyses. 3D finite difference model of Ilısu dam is modelled using FLAC3D software based on the finite difference method. Two different special creep material models are considered in the numerical analyses. Wipp-creep viscoplastic material model and burger-creep viscoplastic material model were rarely used for the creep analyses of CFRDs in the last are taken into account for the concrete slab and rockfill materials-foundation, respectively. Moreover, interface elements are defined between the concrete slab-rockfill materials and rockfill materials-foundation to provide interaction condition for 3D model. Firstly, dam and foundation are collapsed under its self-weight and static behaviour of the dam is evaluated for the empty reservoir conditions. Then, reservoir water is modelled considering maximum water level of the dam and time-dependent creep analyses are performed for maximum reservoir condition. In this paper, maximum principal stresses, vertical-horizontal displacements and pore pressures that may occur on the dam body surface during 30 years (from 2017 to 2047) are evaluated in detail. According to numerical analyses, empty and maximum reservoir conditions of Ilısu dam are compared with each other in detail. 4 various nodal points are selected under the concrete slab to better seen viscoplastic behaviour changes of the dam and viscoplastic behaviour differences of these points during 30 years are graphically presented. It is clearly seen that horizontal-vertical displacements and principal stresses for maximum reservoir condition are more than the empty reservoir condition of the dam and significant pore pressures are observed during 30 years for maximum reservoir condition. In addition, horizontal-vertical displacements, principal stresses and pore pressures for 4 nodal points obviously increased until a certain time and changes decreased after this time.

• Structural Engineering and Mechanics
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• 제28권4호
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• pp.411-442
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• 2008

Ground motions in near source region of large crustal earthquakes are significantly affected by rupture directivity and tectonic fling. These effects are the strongest at longer periods and they can have a significant impact on Engineering Structures. In this paper, it is aimed to determine near-fault ground motion effects on the nonlinear response of dams including dam-reservoir-foundation interaction. Four different types of dam, which are gravity, arch, concrete faced rockfill and clay core rockfill dams, are selected to investigate the near-fault ground motion effects on dam responses. The behavior of reservoir is taken into account by using Lagrangian approach. Strong ground motion records of Duzce (1999), Northridge (1994) and Erzincan (1992) earthquakes are selected for the analyses. Displacements, maximum and minimum principal stresses are determined by using the finite element method. The displacements and principal stresses obtained from the four different dam types subjected to these nearfault strong-ground motions are compared with each other. It is seen from the results that near-fault ground motions have different impacts on the dam types.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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• pp.653-656
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• 2008

본 연구의 목적은 댐의 설계 및 건설에 있어 댐 콘크리트의 내구성을 향상시키기 위한 것이다. 특히, 콘크리트 표면 차수벽형 석괴댐(Concrete Faced Rockfill Dam)의 경우 표면 차수벽 콘크리트의 내구성은 시멘트의 일부를 플라이애쉬로 치환하고 blended 섬유(고인성 섬유 + 일반 섬유)를 사용함으로써 향상될 수 있다. 따라서 본 연구에서는 플라이애쉬의 치환율 및 blended 섬유의 혼입율에 따른 표면 차수벽 콘크리트의 내구성과 열특성 실험을 수행하고 그 효과를 분석하였다. 실험결과 플라이애쉬 치환율은 15%, blended 섬유의 혼입율은 0.1%(고인성 섬유 $0.09kg/m^3$ + 일반 섬유 $0.81kg/m^3$)인 경우 내구성 측면에서 가장 우수한 결과를 보여 주었으며, 특히 다른 배합에 비하여 균열발생 가능성이 상대적으로 낮은 것으로 나타났다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.1219-1226
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• 2005

In this study, crest settlement characteristics of CFRD (Concrete Faced Rockfill Dam) and ECRD (Earth Cored Rockfill Dam) were analysed through the instrumentation data from representative 7 large dams in Korea. Also, We have studied the effect of valley shape and uniaxial compressive strength of intact rock to better understand the impact of the parent rock strength and the valley shape on the long term crest settlement of CFRDs. From the results, we found that the valley shape and strength of intact rock on crest settlement of dams are an important parameters. As a result, we obtained that the maximum crest settlement of CFRD is larger than that of ECRD and long term crest settlement rate per dam height of rockfill dams is less than 0.60% during service period.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.713-716
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• 2006

The main purpose of this research was to enhance the durability in both the design and construction of dams. Especially, in case of rockfill dams, the durability of tunnel concrete in a concrete-faced rockfill dam(CFRD) is achieved by optimizing the fly ash replacement for cement and application of steel fiber. The effect on durability and thermal property corresponding to the increasing replacement of fly ash and application of steel fiber was evaluated, and the optimum value of fly ash replacement and steel fiber application was recommended. The results show that 15% of fly ash replacement and $20kg/m^3$ of steel fiber application was found to be an optimum level and demonstrated excellent performance in durability and thermal property.

• 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.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.818-823
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• 2006

In this study, the suitability of CFGD(concrete faced gravefill dam) was investigated by examining the strength and deformation characteristics of a gravelfill material, a CFGD main fill material, and comparing them with those of several rockfill dam materials. The gravelfill material exhibited similar strength and deformation properties to those of the main fill materials of existing stable large rockfill dams. Since not only CFGD has environmental and economic advantages over CFRD, but its main fill material compares favorably with those of the existing stable CFRDs, CFGD may be the best choice when natural gravel materials are abundant in the vicinity of the dam construction location.

• 한국지반신소재학회논문집
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• 제8권2호
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• pp.31-39
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• 2009

본 연구에서는 준공 후 정부침하, 콘크리트 슬래브 변형, 누수량 등의 CFRD 거동 예측과 유지 관리 지표로 유용하게 활용될 수 있도록 하기 위해 국내외 27개의 콘크리트 표면차수벽형 석괴댐 (CFRD)의 사례를 분석하였다. 검토결과 Sherard와 Cooke(1987)과 Clements(1984) 등이 제안한 준공 후 정부침하 범위는 록필 재료의 강도가 매우 양호한 경우에는 적합하나, 보통에서 양호한 경우는 과소평가하는 경향이 있는 것으로 나타났다. 누수량 사례분석결과 CFRD에서 누수량의 주원인은 담수하중에 의한 슬래브의 변형이고, 최대 누수량은 주로 최초 담수중에 발생하고, 댐 높이가 125m보다 커지게 되면 누수량이 급증하는 경향이 있는 것으로 나타났다.