• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.328-334
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• 2003

Evaluating stability of dam foundations is one of the prime areas of any rock engineering investigations. Despite best engineering efforts in the design and construction of dam foundations, the foundation regime of a constructed dam suffers deterioration due to continuous erosion from backwater current of dam discharge and dynamic effects of loading and unloading process. Even during construction, development of frequent cracks due to sudden thermal cooling of concrete blocks is not uncommon. This paper presents two case studies from India and Bhutan. In the first case, the back current of water discharge from the Srisailam dam in India had continuously eroded the apron and has eaten into the dam foundation. In the second case with dam construction at Tala Hydroelectric Project in Bhutan, sudden overflow of river during the construction stage of dam had led to development of three major cracks across the dam blocks. This was ascribed to adiabatic cooling effect of concrete blocks overlain by chilled water flow. Non-destructive evaluation of rock mass condition in the defect regime by the borehole GPR survey helped in arriving at the crux so as to formulate appropriate restoration plan.

• 한국농공학회논문집
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• 제58권2호
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• pp.11-20
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• 2016

Korea has 17,500 irrigation dams and facing variety of causes that jeopardize dam safety. With limited resources available to manage large inventory, a portfolio risk analysis application method for numerous irrigation dam safety is essential. The purpose of this study is to find an optimum way to adopt the risk analysis to the large number of irrigation dams in Korea and to propose the portfolio risk analysis process for irrigation dams. In this study, the necessity of the risk analysis for reservoirs safety has been suggested and a phased process using pre-screening and screening methodology has been proposed. This proposed procedure will help to effectively introduce the risk analysis for reservoirs safety in Korea.

• 한국습지학회지
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• 제8권1호
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• pp.97-106
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• 2006

This study discusses two canceled dam projects, Youngwol Dam in South Korea and Two Forks Dam in Colorado of the United States. Both of them illustrate how the new paradigm applies to regional water projects because they became victims of environmental opposition in the new paradigm. While the cases have no apparent close relationships and they occurred in different decades, they offer interesting comparisons. They were basically struggles between water development coalitions and environmental protection coalitions on regional water conflicts. The two proposed projects brought about fierce debates on large dam as they embraced a wide-range of environmental, social, and political issues rather than construction of dams themselves. Huge anti-dam oppositions scrapped them at the cost of nearly ten years for decision-makings and enormous financial resources for feasibility studies respectively. It identifies who the policy actors were, what the policy strategies were, and how the water policies evolved in both countries. The decision-makings on the two projects appeared at first glance to be made under formal institutional frameworks, but in actuality, they relied significantly on decisions of the two important political actors. The Korean society began to learn negotiation and cooperation approaches to solve the water conflict by establishing the Joint Task Force Team on Youngwol project in 1999. The team is recognized as a new conflict resolution method in South Korea because a diverse of stakeholder interests voluntarily participated in the decision-making process and discussed water issues directly. Even though the projects resulted in futile fruits in each country, they illustrate the images of the new paradigm that significantly affected in formulating regional water policies in South Korea and the United States.

• 한국수자원학회논문집
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• 제41권10호
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• pp.1009-1021
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• 2008

본 연구에서는 댐이 하류하천에 미치는 영향권을 산정하기 위하여 수리 수문적, 지형적, 환경 생태적, 사회적 영향의 4개 지표와 38개 항목을 선정하고, 계층분석법을 적용하여 댐의 영향권 산정 지표와 항목의 중요도를 평가하였다. 댐 영향권 산정 지표의 평가결과는 수리 수문적 영향권이 1순위, 환경 생태적 영향권이 2순위, 지형적 영향권 및 사회적 영향권이 각각 3순위와 4순위 이었으며, 항목의 평가결과는 댐설계방류량이 1순위, 하천의 기본 및 계획홍수량이 2순위, 계획홍수량비가 3순위, 유역면적비가 4순위, 하류댐 배수위가 5순위로 평가되었다. 대청댐의 영향권을 산정한 결과, 댐설계방류량 지표는 47.21 km, 하천계획홍수량 지표는 45.71 km, 유역면적비 지표는 13.94 km로 산정되었다.

• Structural Engineering and Mechanics
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• 제37권6호
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• pp.593-615
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• 2011

This study determines the water length effects on the modal behavior of a prototype arch dam using Operational and Analytical Modal Analyses. Achievement of this purpose involves construction of a prototype arch dam-reservoir-foundation model under laboratory conditions. In the model, reservoir length was taken to be as much as three times the dam height. To determine the experimental dynamic characteristics of the arch dam using Operational Modal Analysis, ambient vibration tests were implemented for empty reservoir and three different reservoir water lengths. In the ambient vibration tests, the dam was vibrated by natural excitations provided from small impact effects and the response signals were measured using sensitive accelerometers. Operational Modal Analysis software process signals collected from the ambient vibration tests, and Enhanced Frequency Domain Decomposition and Stochastic Subspace Identification techniques estimated modal parameters of the dams. To validate the experimental results, 3D finite element model of the prototype arch dam was modeled by ANSYS software for empty reservoir and three different reservoir water lengths, and dynamic characteristics of each model were determined analytically. At the end of the study, experimentally and analytically identified dynamic characteristics compared to each other. Also, changes on the natural frequencies along to water length are plotted as graphs. Results suggest that reservoir water complicates the modal behavior of the arch dam significantly.

• Steel and Composite Structures
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• 제49권6호
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• pp.701-711
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• 2023

In order to fully reflect variation characteristics of composite concrete dam health state, the monitoring data is applied to diagnose composite concrete dam health state. Composite concrete dam lesion development to wreckage is a precursor, and its health status can be judged. The monitoring data are generally non-linear and unsteady time series, which contain chaotic information that cannot be characterized. Thus, it could generate huge influence for the construction of monitoring models and the formulation of corresponding health diagnostic indicators. This multi-scale diagnosis process is from point to whole. Chaotic characteristics are often contained in the monitoring data. If chaotic characteristics could be extracted for reflecting concrete dam health state and the corresponding diagnostic indicators will be formulated, the theory and method of diagnosing concrete dam health state can be huge improved. Therefore, the chaotic characteristics of monitoring data are considered. And, the extracting method of the chaotic components is studied from monitoring data based on fuzzy dynamic cross-correlation factor method. Finally, a method is proposed for formulating composite concrete dam health state indicators. This method can effectively distinguish chaotic systems from deterministic systems and reflect the health state of concrete dam in service.

• Structural Engineering and Mechanics
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• 제48권1호
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• pp.17-39
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• 2013

In the present paper, a coaxial rotating smeared crack model is proposed for mass concrete in three-dimensional space. The model is capable of applying both the constant and variable shear transfer coefficients in the cracking process. The model considers an advanced yield function for concrete failure under both static and dynamic loadings and calculates cracking or crushing of concrete taking into account the fracture energy effects. The model was utilized on Koyna Dam using finite element technique. Dam-water and dam-foundation interactions were considered in dynamic analysis. The behavior of dam was studied for different shear transfer coefficients considering/neglecting fracture energy effects. The results were extracted at crest displacement and crack profile within the dam body. The results show the importance of both shear transfer coefficient and the fracture energy in seismic analysis of concrete dams under high hydrostatic pressure.

• 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.

• 한국농공학회논문집
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• 제55권3호
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• pp.1-7
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• 2013

The dam plan quantity of constructive and water supply quantity of present time are showing a difference with change in climate and augmentation of water demand for multipurpose dams in Nakdong river basin. But revaluates a water supply ability the method or the process is official for is not taking a position, so actual condition applies the plan quantity of dam constructive. Considers various situation of actual multipurpose dam from research sees consequently and in K-WEAP is an integrated water resources evaluation plan model applies as water permit availability multipurpose dam, currently water permit availability comparison, analyzed. In this study, the natural daily flow data and apply the dimensions of the reservoir, and for more than 30 years of the long-term water balance analysis conducted by Date Nakdong river basin can supply reservoirs are large quantity of permits available is presented.

• Journal of Advanced Marine Engineering and Technology
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• 제32권8호
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• pp.1221-1230
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• 2008

Inflatable rubber dams are used for controlling flood, impounding water for recreations, preventing beach erosions, diverting water for irrigations, and generating hydropower. They are long, flexible, inflated with air, cylindrical structures on a rigid horizontal foundation such as concrete. The dam is modeled as an elastic shell inflated with air. The mechanical behaviors of the inflated dam model were investigated by using the finite element method. The analysis process such as One Way Coupling Fluid-Structure Interaction consists of two steps. First, the influences of the fluid side were investigated, viz, the shape changes of the inflated rubber dam due to the fluid motions was captured when the height of the dam was 30cm with air pressure 0.01MPa, at which the pressure distributions over the surface of the dam were calculated. And next, the structural deformations were calculated using the pressure distributions. The initial inlet velocity for flow field was set to 0.1m/s. The structural deformation behaviors were investigated. The final research goal is to develop a Korean Inflatable Rubber Dam to be used for generating small hydropower.