• Journal of Korea Water Resources Association
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• v.48 no.10
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• pp.781-791
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• 2015

Dam risk analysis requires a systematic process to ensure that hydrologic variables (e.g. precipitation, discharge and water surface level) contribute to each other. However, the existing dam risk approach showed a limitation in assessing the interdependencies across the variables. This study aimed to develop Bayesian network based dam risk analysis model to better characterize the interdependencies. It was found that the proposed model provided advantages which would enable to better identify and understand the interdependencies and uncertainties over dam risk analysis. The proposed model also provided a scenario-based risk evaluation framework which is a function of the failure probability and the consequence. This tool would give dam manager a framework for prioritizing risks more effectively.

• Journal of the Korean Geotechnical Society
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• v.31 no.8
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• pp.51-62
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• 2015

It is not possible to provide resonable evidence for embankment (or dam) overtopping in geotechnical engineering, and conventional analysis by hydrologic design has not provided the evidence for the overflow. However, hydrologic design analysis using Copula function demonstrates the possibility that dam overflow occurs when estimating rainfall probability with rainfall data for 40 years based on fluctuating water level of a dam. Hydrologic dam risk analysis depends on complex hydrologic analyses in that probabilistic relationship needs to be established to quantify various uncertainties associated with modeling process and inputs. The systematic approaches to uncertainty analysis for hydrologic risk analysis have not been addressed yet. In this paper, the initial level of a dam for stability of a dam is generally determined by normal pool level or limiting the level of the flood, but overflow of probability and instability of a dam depend on the sensitivity analysis of the initial level of a dam. In order to estimate the initial level, Copula function and HEC-5 rainfall-runoff model are used to estimate posterior distributions of the model parameters. For geotechnical engineering, slope stability analysis was performed to investigate the difference between rapid drawdown and overtopping of a dam. As a result, the slope instability in overtopping of a dam was more dangerous than that of rapid drawdown condition.

• The Journal of Dong Guk Oriental Medicine
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• v.8 no.1
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• pp.133-144
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• 1999

"Dan-eum(痰飮)" is the pathological product which is developed in the progress of disease. "Dam-eum" itself can be an etiological factor and id developed as consequential products on diseases. This study is investigated into "Dam-eum" and stroke through the literature since the book, "Hwangje-naekyong(黃帝內經)" and the results are as follows. 1. "Dam-em" is the pathological product, which is changed into "Yol-Dam(熱痰)", "Pung-dam(風痰)" and "Seub-dam(濕痰)", owing to the disorders of diet and "Chil-jung(七情)", infirmity of "Jung-ki(精氣)", "Oi-gam-yuk-em(外感六淫)", constitutional factors and so forth. In is blocked up "Jangbu-Kyongrak(臟腑經絡)" and brings about stroke with the disorders in circulation of "Gi-hyul(氣血)". 2. "Dan-em" is formed out of "Jin-aek(津液)", which is changed through the pathological process of "Gi-cheh(氣體)", "Hwa-yoi(化鬱)" and "Han-eng(寒凝)". In the meanwhile, the brain keeps its function with nutrition of "Jin-aek", If "Dam-eum" is formed by deficiency and circulation disorders of "Jin-aek", it can affect the brain 3. "Dam-eum" is correlated with "Eo-hyul(瘀血)", and the pathological transformations. In the attack of stroke. "Dam-eum" precedes "Eo-hyul", in reverse or the two are concurrent with each other.

• Journal of the Korean Society of Industry Convergence
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• v.8 no.2
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• pp.113-120
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• 2005

Due to the Typhoon MAEMI on Sep. of 12 in 2003, the turbidity value of DOAM Dam was recorded more than 300NTU until now. The natural zeolite located in the east coast of Korean peninsula was applied to reduce turbidity with cation exchange process. The result of this technique, the value of turbidity was reduced less than 1NTU. Also the value of pH showed stable state compare to before and after.

• Structural Monitoring and Maintenance
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• v.4 no.1
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• pp.85-105
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• 2017

Monitoring is the most important part of the construction and operation of the embankment dams. Applied instruments in these dams should be determined based on dam requirements and specifications. Instruments selection considered as one of the most important steps of monitoring plan. Competent instruments selection for dams is very important, as inappropriate selection causes irreparable loss in critical condition. Lack of a systematic method for determining instruments has been considered as a problem for creating an efficient selection. Nowadays, decision making methods have been used widely in different sciences for optimal determination and selection. In this study, the Multi-Attribute Decision Making is applied by considering 9 criteria and categorisation of 8 groups of geotechnical instruments. Therefore, the Analytic Hierarchy Process and Multi-Criteria Optimisation and Compromise Solution methods are employed in order to determine the attributes' importance weights and to prioritise of instruments for embankment dams, respectively. This framework was applied for a rock fill with clay core dam. The results indicated that group decision making optimizes the selection and prioritisation of monitoring instruments for embankment dams, and selected instruments are reliable based on the dam specifications.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.4
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• pp.433-447
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• 2023

There is a growing demand for the stability of existing dams due to abnormal climate and the aging of dams. Emergency Action Plans (EAPs) for reservoir or dam failure only consider a single rainfall event. Therefore, this study simulates dam failure caused by continuous rainfall events, and proposes the establishment of EAP by selecting the optimal shelters. We define a mega rainfall event scenario caused by continuous rainfall events with 500-year frequency in the Chungju Dam watershed and estimate the mega flood. The mega flood event scenario is divided into two cases: scenario A represents the flooding case caused by discharge release from a dam, while scenario B is the case of a dam break. As a result of flood inundation analysis, the flooded damage area by the scenario A is 50.06 km² and the area by the scenario B is 6.1 times of scenario A (307.45 km²). We select optimal shelters for each administrative region in the city of Chungju, which has the highest inundation rate in the urban area. Seven shelter evaluation indicators from domestic and foreign shelter selection criteria are chosen, and Analytical Hierarchy Process (AHP) method is used to evaluate the alternatives. As a result of the optimal shelter selection, the six shelters are selected and five are schools. This study considers continuous rainfall events for inundation analysis and selection of optimal shelters. Also, the results of this study could be used as a reference for establishment of the EAP.

• Journal of Korea Water Resources Association
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• v.55 no.7
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• pp.515-529
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• 2022

Identifying the available water resources amount is an essential process in establishing a sustainable water resources management plan. Dam facility is a major infrastructure storing and supplying water during the dry season, and the water supply yield of the dam varies depending on dam inflow conditions or operation rule. In South Korea, water supply yield of dam is calculated by reservoir simulation based on observed historical dam inflow data. However, the water supply capacity of a dam can be underestimated or overestimated depending on the existence of historical drought events during the simulation period. In this study, probabilistic inflow data was generated and used to estimate the appropriate range of the water supply yield of hydropower dams. That is, a method for estimating the probabilistic dam inflow that fluctuates according to climatic and socio-economic conditions and the range of water supply yield for hydropower dams was presented, and applied to hydropower dams located in the Han river in South Korea. It is expected that the understanding water supply yield of the hydropower dams will become more important to respond to climate change in the future, and this study will contribute to national water resources management planning by providing potential range of water supply yield of hydropower dams.

• Journal of the Korea Concrete Institute
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• v.12 no.3
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• pp.31-37
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• 2000

When a crack is produced in a concrete structure, a micro crack zone of fracture process zone (FPZ) appears at the crack tip. To investigate the behaviour of this the micro crack zone, nonlinear fracture mechanics (NLFM) must be applied. However, when a massive concrete structure such as a concrete gravity dam is considered, the micro crack zone can be neglected and the structure can be assumed to have linear elastic fracture mechanics (LEFM) behaviour. This study is divided into two main topics : (1) Calculating stress intensity factor (SIF) at the crack tip by surface integral method and (2) Investigating the propagation of the initial crack. If the initial crack propagates, the angle of the propagation is calculated by using maximum circumferential tensile strength theory. This study, also, contains the effects of body forces and water pressures on the crack face.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.3
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• pp.72-78
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• 1992

The Silicon vertical Hall devices are fabricated using standard bipolar process and characterized in terms of the Hall voltage, sensitivities, and offset voltage. The Hall voltage and sensitivity of the devices showed good linearity with respect to the magnetic flux density and reverse supply voltage Vr. The sensitivity of device with P$^{+}$ isolation dam has been increased up to 1.2 times compared to that of device without the dam. With the condition of V$_{r}$=-5.0[V], B=0.4[T] and I$_{sup}$=1.0[mA], the Hall voltage and sensitivity of the device with P$^{+}$ isolation dam were about 29[mV] and 74[V/AT], respectively. These vertical Hall devices can be used as the adjustable magnetic fields sensor.

• Computers and Concrete
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• v.13 no.5
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• pp.633-648
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• 2014

The seismic safety of concrete dams is one of the important problems in the engineering due to the vast socio-economic disasters which may be caused by collapse of these infrastructures. The accuracy of the risk evaluation associated with these existing dams as well as the efficient design of future dams is highly dependent on a proper understanding of their behaviour due to earthquakes. This paper develops an anisotropic damage model for arch dam under strong earthquakes. The modified Drucker-Prager criterion is adopted as the failure criteria of the dynamic damage evolution of concrete. Some process fields and other necessary information for the safety evaluation are obtained. The numerical results show that the seismic behaviour of concrete dams can be satisfactorily predicted.