• Title, Summary, Keyword: CFRD(Concrete Faced Rockfill Dam)

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Analysis of CFRD(Concrete Faced Rockfill Dam) Constructed by Stages (단계축조에 의해 시공된 CFRD의 거동해석)

  • Cho, Sung-Eun;Shin, Dong-Hoon;Jeon, Je-Sung;Kim, Ki-Young
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.583-588
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    • 2005
  • In this study, a concrete faced rockfill dam constructed by stages was numerically analyzed, and the numerical results were compared with in situ measurements. The simple incremental elastic and isotropic hyperbolic model was employed to characterize the nonlinear deformation behavior of rockfill material and computational procedure followed construction sequence. A series of large triaxial tests for rockfill material were carried out to obtain mechanical input parameters. According to the analysis results, relative great additional deformation was introduced at the surface of stage-I dam body due to the loading by stage-II construction. The results reveal that numerical analysis can effectively simulate the construction processes, and some meaningful insights about the behavior of CFRD during construction were gained.

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

  • Park Dong-Soon;Kim Hyoung-Soo
    • The Journal of Engineering Geology
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    • v.16 no.1
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    • pp.97-107
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    • 2006
  • Or this study, prevailing design and construction methods of dam under various unfavorable conditions are summarized. for example, foundation treatment with large scale alluvium site or weathered rock mass, dam constructing techniques with unfavorable topographic conditions are studied for the better understanding of relating engineers. Also, zoning by using weak rocks and sand-gravel fill techniques are summed up.

Suitability of Concrete Faced Gravelfill Dam(CFGD) (콘크리트표면차수벽형 사력댐(CFGD)의 적용성 고찰)

  • Kim, Bum-Joo;Im, Eun-Sang;Lim, Jeong-Yeul;Park, Han-Gyu;Lim, Heui-Dae
    • Proceedings of the Korean Geotechical Society Conference
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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.

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

  • Park Dong-Soon;Kim Hyoung-Soo;Lim Jeong-Yeul
    • The Journal of Engineering Geology
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    • v.15 no.1
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    • pp.77-86
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    • 2005
  • CFRD(Concrete Faced Rockfill Dam) is in widespread use because this type of dam has superior characteristics in structural, material aspects comparing with earth cored rockfill dam. On this paper, up-to-date re-searches and techniques are summed up to be available for future needs in design and construction of CFRD. For example, such items as embankment using weak rock, experience of sand-gravel fill CFRD, connecting slab applied between plinth and face slab, raising experience of old dm, inverse filtration problem, environmental friendly zone, thickness and reinforcing of face slab, alluvial foundation treatment, and curb element method, are summarized for understanding of related engineers.

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

  • Kim Yong-Seong
    • Journal of The Korean Society of Agricultural Engineers
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    • v.48 no.4
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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.

Compaction Management of Fill Materials for Concrete Faced Rockfill Dam Using Standard Void Ratio (표준간극비를 이용한 콘크리트 표면차수벽형 석괴댐 축조재료의 다짐 관리)

  • Kim Yong-Seong
    • Journal of The Korean Society of Agricultural Engineers
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    • v.48 no.4
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    • pp.59-66
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    • 2006
  • In this study, construction modulus, void ratio and settlement characteristics of 38 CFRD in domestic and foreign countries were investigated from monitoring data. The effect of field dry density and void ratio to dam body was analyzed. The standard void ratio of CFRD that can be easily used by dam designers and field engineers was proposed from the monitoring data. It was confirmed that we can get the degree of compaction needed for reasonable compaction of dam body by calculating the field dry density from inverse operation of the standard void ratio. It was thought that the void ratio of CFRD depends on shape coefficient and in case of a high shape coefficient, the void ratio was high with its void ratio 0.17 -0.38.

A Study on Settlement Prediction of Concrete-faced Rockfill Dam Using Measured Data During Construction and After Impounding (시공 중 및 담수 후 계측데이터를 이용한 CFRD의 침하량 예측 연구)

  • Lee, Chungwon;Kim, Yongseong
    • Journal of the Korean GEO-environmental Society
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    • v.16 no.2
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    • pp.5-13
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    • 2015
  • In the present study, the prediction methods of the crest settlement after impounding and the maximum internal settlement during dam construction were proposed through the analysis on settlement data at 38 monitored points of 36 Concrete-Faced Rockfill Dams (CFRDs). The results from this analysis provided that the crest settlement and the maximum internal settlement are increased in proportion to the dam height and the void ratio. However, the relationship between internal settlement and dam height for each void-ratio range plotted in semi-logarithmic scale is the nearly same. Also, the prediction of the crest settlement of the CFRD is possible through the maximum internal settlement during dam construction. In addition, it seems that the valley shape highly affects the dense dam body with high construction modulus. The results of this study will provide the useful tool for the design, construction and management of CFRDs.

A Study on Crest Settlement Characteristics of Rockfill Dam (락필댐의 정부침하 거동특성 연구)

  • Park, Han-Gue;Park, Dong-Soon;Kim, Yong-Seong;Lee, Jong-Wook
    • Proceedings of the Korean Geotechical Society Conference
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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.

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Analysis of post-construction deformation characteristics of concrete faced rockfill dams

  • Kim, You-Seong;Won, Myoung-Soo;Song, Young-Chul;Yoon, Deok-Joong
    • Proceedings of the Korean Geotechical Society Conference
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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.

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Sensitivity Analysis of Rockfill Parameters Influencing Crest Displacements of CFRD Subjected to Earthquake Loading (지진하중을 받는 필댐 정부변위에 영향을 미치는 입력물성에 대한 민감도 분석)

  • Ha, Ik-Soo;Shin, Dong-Hoon
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.351-357
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    • 2006
  • In this study, quantitative sensitivity analysis on rockfill material influencing the dam crest displacement of Concrete-Faced Rockfill Dam(CFRD) subjected to earthquake loading was carried out. The purpose of this study is to indicate the most important input parameter and to show the quantitative variation of displacement at the crest of CFR type dam during earthquake loading with this input parameter. From the sensitivity analysis, it was found that the crest displacement of CFR type dam subjected to dynamic loading was absolutely affected by the shear modulus of rockfill material and the effect of friction angle of it was negligible. This relative difference of sensitivity was more outstanding in case of crest settlement than in case of crest horizontal displacement. Also, it was found that the extent of effect of shear modulus on the displacement at the crest of CFRD due to dynamic loading decreased as maximum amplitude of input acceleration increased.

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