• 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.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.37 no.3
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• pp.163-171
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• 2024

Structural health monitoring for ships and offshore structures is important in various aspects. Ships and offshore structures are continuously exposed to various environmental conditions, such as waves, wind, and currents. In the event of an accident, immense economic losses, environmental pollution, and safety problems can occur, so it is necessary to detect structural damage or defects early. In this study, structural response data of multi-linked floating offshore structures under various wave load conditions was calculated by performing fluid-structure coupled analysis. Furthermore, the order reduction method with distortion base mode was applied to the structures for predicting the structural response by using the results of numerical analysis. The distortion base mode order reduction method can predict the structural response of a desired area with high accuracy, but prediction performance is affected by sensor arrangement. Optimization based on a genetic algorithm was performed to search for optimal sensor arrangement and improve the prediction performance of the distortion base mode-based reduced-order model. Consequently, a sensor arrangement that predicted the structural response with an error of about 84.0% less than the initial sensor arrangement was derived based on the root mean squared error, which is a prediction performance evaluation index. The computational cost was reduced by about 8 times compared to evaluating the prediction performance of reduced-order models for a total of 43,758 sensor arrangement combinations. and the expected performance was overturned to approximately 84.0% based on sensor placement, including the largest square root error.

• 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 GEO-environmental Society
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• v.8 no.6
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• pp.77-83
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• 2007

In this study, deformation behavior of existing concrete face rockfill dam, which is raised to a certain height to enhance storage capacity or to improve hydraulic and hydrologic stability, is examined using numerical analysis method. The results obtained from FEM analysis show a possibility that additional fill at downstram slope of existing CFRD dam body may lead undesirable deformations and stresses in existing dam body, especially in face concrete, such as settlements in upper part and bulging in lower part, excessive bending moments, and eventualy tensile cracks. Therefore, in designing multi-staged raising construction of CFRD, it is essential to consider deformations and stresses to be developed within and between exisiting dam body and added parts due to additional fill, and to prepare a proper measure to prevent abnormal deformations and stresses in the dam body including added parts.

• 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 Geotechnical Society
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• v.20 no.4
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• pp.29-38
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• 2004

A finite element nonlinear stress-deformation model with multi-interface element is applied to the stability analysis of waste landfill slope. Strength parameters of waste and geosynthetic materials are obtained from the triaxial test of waste and the direct shear test of geosynthetics, respectively. The landfill models used for the numerical models are fit to regulations of the Korean waste management law. The results of the strength tests showed linear behavior for the waste and nonlinear behavior for the eosynthectic materials. The stability analysis with multi-interface element for the geosynthetic materials in the liner system showed large shear stress and slippage at the boundary of the foundation and the slope of the waste fill. This analysis verified the necessity of multi-interface analysis for waste landfills with composite liners.

• Proceedings of the Optical Society of Korea Conference
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• 1991.06a
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• pp.168-171
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• 1991

홀로그래피 간섭무늬로부터 변형의 요철방향을 구하기 위하여 무늬반송법을 응용하였다. 변형에 의해 형성된 간섭무늬의 차수가 기준무늬를 따라 한 방향으로 증가하도록 하였으며, 디자탈 영상처리 기술을 이용하여 간섭무늬 해석을 자동화 하였다.

• 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.

• Journal of the Korean GEO-environmental Society
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• v.14 no.1
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• pp.53-60
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• 2013

On this study, engineering properties of SGR method and SMI method, which are typical sodium silicate methods, were compared through the laboratory test and durability, strength, waterproof characteristic and environmental effects were compared and analyzed with period and condition of curing on each case. As a result of durability test, volume change of SGR is approximately 23-times greater than SMI and the effects on environment are appeared safe on all method. In case of waterproof characteristic test, permeability coefficient is decreased about 24% on SMI, whereas on SGR permeability coefficient is showed to increase because rapid volume change make wider void. Strength characteristics of SMI are appeared higher about 11-times in case of homogel and 3.9-times in case of sandgel than SGR. Which is because volume change of SMI, caused by leaching, is smaller than SGR.

• Journal of the Korean GEO-environmental Society
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• v.24 no.11
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• pp.5-10
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• 2023

Slag-CB is widely used in various fields that require groundwater control. It is a type of CB where a portion of the cement mixed with CB is replaced with GGBS. In general, Slag-CB has the advantage of long-term improvement in compressive strength, permeability, durability, and chemical resistance as the GGBS replacement ratio increases. However, there are problems such as decreased flexibility and resistance to deformation of the cut-off walls, as well as brittleness upon failure. To address these problems, some quality standards recommend designing Slag-CB with lower strength, which makes it challenging to apply high-strength Slag-CB with a high GGBS replacement ratio in the field.In this study, we aimed to improve the flexibility and resistance to deformation of Slag-CB to prevent brittle failure and improve the field applicability of Slag-CB. To achieve this, we evaluated the compressive behavior of nylon fiber-reinforced Slag-CB and proposed measures for enhancing the flexibility and resistance to deformation of Slag-CB.