• The Journal of Engineering Geology
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• v.16 no.1 s.47
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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.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.3C
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• pp.209-218
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• 2006

In this study, stress and deformation of CFRD during its construction and impounding were analyzed and compared with its monitoring results. Moreover, deformation characteristics of CFRD after impounding were evaluated based on the settlement monitoring records of total 23 domestic and foreign CFRDs during construction and impounding. The investigation on the behavior of CFRD indicated that the influence of impounding on its stability was minimal although slight increases in vertical and horizontal stresses and strains were observed. Also, one method was proposed to predict a crest settlement from multi-layer settlements by applying the best fit method. It is expected that the results of this study would provide practical information for the design, construction, and management of CFRD.

• The Journal of Engineering Geology
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• v.19 no.4
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• pp.493-499
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• 2009

Recently, the construction of Concrete Faced Rockfill Dam (CFRD) is increasing because rock material resources are plenty in Korea. Bedding zone in the CFRD is necessary enough bearing capacity to support the concrete face slab uniformly and enough impermeability to prevent the loss of fine soils in case of leakage from the concrete slab face. Therefore, cut-off the water leakage in bedding zone securely is the key factor influencing the safety of CFRD. Tested materials satisfied with the specification of particle size distribution at the Bedding Zone area are chosen for conducting permeability tests, which are done to evaluate the property of cut off the materials. Based on the test results, the effects of cut off the materials are investigated by considering the coefficient of permeability, the soil particle distribution, and the dry unit weight. Especially, the relationships between coefficient of permeability with effective size(D10), dry unit weight, and weight passing percent the No.4 sieve are suggested, and also the variation of coefficient of permeability with time are proposed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.3
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• pp.140-148
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• 2016

This study examined the durability of face-slab concrete in Concrete-Faced Rock-filled Dams(CFRDs). The durability of face-slab concrete can be improved by optimizing the amount of fly ash in the cement mixture. Durability tests including plastic shrinkage, permeability, abrasion resistance, and repeated freezing and thawing were done on face-slab concrete specimens with different amounts of fly ash and blended PVA(Poly Vinyl Alcohol) fibre. When the effect of the fly ash content on concrete durability was evaluated, the results showed that a 15% fly ash content and 0.1% blended PVA fiber yielded the optimum durability level for concrete-faced rock-filled dams.

• Journal of the Korean Geosynthetics Society
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• v.6 no.2
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• pp.9-15
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• 2007

Bedding zone in CRFD (Concrete Faced Rockfill Dam) requires bearing capacity to support the concrete face slab uniformly. Also, shear strength which is a key factor in slope stability and impermeability which is to prevent a loss of soils in case of leakage of concrete slab face are needed. In this study, trial prototype construction for bedding zone in CRFD was performed to investigate the compaction characteristics of bedding zone according to the frequency of compaction, water contents and so on. As a results of series of field test, the compaction characteristics of bedding zone in CRFD was affected considerably by the depth of compaction layer and frequency of compaction.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.1
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• pp.129-139
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• 2015

Concrete-Face Rock-Fill Dams (CFRDs) are rock-fill dams with watertight-concrete slabs on its upstream slope instead of its central earth cores. The design for CFRDs are still largely empirical and typically based on past experiences. This paper presents a description of the concrete face slabs and leakage behaviors of two post-constructed CFRDs based on the data gathered through instrumentation during the initial impoundment. The results show that the strain on the concrete face slab and the horizontal displacements of the vertical slab joints are slightly affected by both the seasonal temperature change and water loading during the initial impoundment. The deformation of perimetric joints are less affected by the temperature change, however it is significantly affected by the water loading during the initial impoundment. The leakage rate is significantly affected by the hydrostatic load and the deformation of the perimetric joints.

• Journal of the Korean GEO-environmental Society
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• v.14 no.11
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• pp.33-46
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• 2013

Recently, the projects which are to increase the capacity of the flood control are being actively performed because of the abnormal climate changes throughout the country. In this study, the regression analysis was performed using both Kelvin model and the real settlement measured at the crest of the existing concrete face rockfill dam(CFRD) to estimate the long-term deformation behavior characteristics such as creep which occurs without additional load. In addition, the effects on changes in physical properties (E, G, K) of the dam construction materials by deformation characteristics of the dam were evaluated, and the reasonable stability analysis method of the dam was proposed to obtain the long-term stability considering the changes in physical properties induced by the long-term deformation behavior in case of heightening the existing dams.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.653-656
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• 2008

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 face slab concrete in a concrete-faced rockfill dam(CFRD) is achieved by optimizing the fly ash replacement for cement and application of blended fiber. The effect on durability and thermal property corresponding to the increasing replacement of fly ash and application of blended fiber was evaluated, and the optimum value of fly ash replacement and blended fiber application was recommended. The results show that 15% of fly ash replacement and 0.9kg/m3 of blended fiber application was found to be an optimum level and demonstrated excellent performance in durability and thermal property.

• Journal of the Korean Geotechnical Society
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• v.20 no.8
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• pp.167-180
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• 2004

In this study finite element analysis using hyperbolic model was performed to predict the characteristics of stress-strain behaviour on concrete face earth dam (CFED : a tentative name) raised with coarse-grained materials corresponding to the face slab bedding zone of concrete face rockfill dam (CFRD). The results of finite element analysis were compared with field monitoring data, and the comparison showed a good agreement. And, the analysis results including locus of maximum displacement, maximum stress, stress concentration, and irregular load transfer would be used to devise rational field monitoring schemes for construction management and quality control during construction of CFED.

• Journal of the Korean Geosynthetics Society
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• v.8 no.2
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• pp.31-39
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• 2009

The purpose of present study performed 27 CFRD cases analyses to predict and effectively use post-construction crest settlement, face slab deformation, and leakage as indexes for the maintenance and management of concrete faced rockfill dams(CFRD). 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 case analyses using rockfills with very high intact strength, but it had a trend which underestimated crest settlement in the cases using rockfills with medium to high intact strength. The leakage case analyses showed that leakage is mainly caused by face slab deformation due to the water load, the maximum leakage in general was observed during the first reservoir filling, and leakage was rapidly increasing when the dam height exceeds 125m.