• 대한토목학회논문집
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• 제33권5호
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• pp.1797-1807
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• 2013

예상하지 못한 자연 현상으로 인해 붕괴될 가능성을 항상 내포하고 있으며 특히 댐 하류부 지역이 인구밀집 지역이거나 중요 국가 시설물이 위치하고 있는 경우에는 인명 및 재산피해 등 막대한 손실을 초래할 수 있다. 지금까지의 연구는 단독댐 붕괴에 따른 홍수파 해석에 대한 연구는 많이 있었으나 세계적으로 유명한 테네시강 등의 순차적 댐이나 우리나라의 북한강 상류로부터 연속으로 이어진 댐 등에 대한 붕괴 홍수파 해석에 대한 연구는 미흡한 실정이다. 따라서 본 연구의 목적은 순차적 댐 붕괴 홍수파 해석을 통해 순차적 댐 붕괴 첨두유량을 계산하고 하류부에서의 홍수파 전파상황을 예측할 수 있는 해석기법을 제시하는데 있다. 이를 위해 DAMBRK를 이용하여 실제 붕괴 사례 중 순차적 댐 붕괴 사례인 Lawn Lake Dam에 대하여 붕괴 홍수파 해석을 실시하여 댐 붕괴 홍수파 해석 모형의 적절성을 검증하였다. 이를 기초로 하여 가상의 극한홍수에 대하여 국내의 A 댐에 대하여 순차적 댐 붕괴 홍수파 해석을 실시하여 홍수파 전파상황을 예측하였으며, 범람 중요 지점에 대하여 2차원 홍수범람해석을 수행하여 1 2차원 홍수파 해석을 비교 분석한 결과 적합도가 90%를 상회하여 1차원 순차적 댐 붕괴 모의의 정확성을 확인할 수 있었다. 이는 순차적 댐 붕괴와 관련된 하천에서의 방재대책 수립을 위한 기본자료를 제공하는데 기여할 수 있을 것으로 판단된다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.874-882
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• 2009

Continuous monitoring of dam performance is essential to earth and rockfill dams safety because it has to be guaranteed for safety during construction period of course and from initial impounding to a long term maintenance period of dam. Among the 31 dams managed by Kwater at present, the proportion of dams being over 20 years after completion of construction is 42% and it is estimated that the loss rate of monitoring devices will be increase as times. Monitoring devices would be impossible to repair since those are mostly installed in the dam body and foundation. If repairing of monitoring devices is possible, the expenditure will be expensive. Therefore reasonable decision making for abandonment, repair and alternation for loss of monitoring devices would be needed through the establishment of key instrument for earth and rockfill dam safety. In this study the process of monitoring for safety were modeled by failure modes of dams, adverse conditions related to failure mode, indicators of adverse condition and monitoring devices The relationship between failure mode and monitoring devices were systematically analyzed and established and evaluation technique for qualifying the importance of monitoring devices were presented.

• Computers and Concrete
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• 제33권5호
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• pp.481-496
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• 2024

Internal erosion around pipes can lead to the failure of earth dams through various mechanisms. This study investigates the displacement patterns in earth dam models under three different failure modes due to internal erosion, using digital image correlation (DIC) methods. Three failure modes—erosion along a pipe (FM1), pipe leakage leading to soil erosion (FM2), and erosion in a pipe due to defects (FM3)—are analyzed using two- and three-dimensional image- processing techniques. The internal displacement of the cross-sectional area and the surface displacement of the downstream slope in the dam models are monitored using an image acquisition system. Physical model tests reveal that FM1 exhibits significant displacement on the upper surface of the downstream slope, FM2 shows focused displacement around the pipe defect, and FM3 demonstrates increased displacement on the upstream slope. The variations in internal and surface displacements with time depend on the segmented area and failure mode. Analyzing the relationships between internal and surface displacements using Pearson correlation coefficients reveals various displacement patterns for the segmented areas and failure modes. Therefore, the image-based characterization methods presented in this study may be useful for analyzing the displacement distribution and behavior of earth dams around pipes, and further, for understanding and predicting their failure mechanisms.

• 물과 미래
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• 제22권2호
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• pp.213-221
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• 1989

점진적인 댐파괴는 흙댐에서 piping이나 overtopping에 의해 시작된다. 점진적 파괴에서는 물의 침식작용에 의해서 파괴부가 형성되고 확대되며 이 과정은 매우 복잡하고 매우 유동적이다. 본 연구에서는 Singh과 Scalatos의 수학적 모형과 Fread의 물리적 모형을 검증하고 비교하였다. Fread의 모형은 많은 입력자료를 필요로하며 충분한 자료가 주어질 때 관측치와 근사함을 보여주었다. Singh과 Scarlatos의 모형은 간단한 입력자료만으로 댐파괴를 근사적으로 모의함을 볼 수 있었다.

• Computers and Concrete
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• 제26권6호
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• pp.483-495
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• 2020

Dams are vital infrastructures that are expected to maintain their stability during seismic excitations. Accordingly, cemented material dams are an emerging type, which are being increasingly used around the world owing to benefiting from advantages of both earth-fill and concrete gravity dams, which should be designed safely when subjected to strong ground motion. In the present paper, the seismic performance of a cemented sand and gravel (CSG) dam is assessed using incremental dynamic analysis (IDA) method by accounting for two failure modes of tension cracking and base joint sliding considering the dam-reservoir-foundation interactions. To take the seismic uncertainties into account, the dam is analyzed under a suite of ground motion records and then, the effect of friction angle for base sliding as well as deformability of the foundation are investigated on the response of dam. To carry out the analyses, the Cindere dam in Turkey is selected as a case study, and various limit states corresponding to seismic performance levels of the dam are determined aiming to estimate the seismic fragilities. Based on the results, sliding of the Cindere dam could be serious under the maximum credible earthquake (MCE). Besides, dam faces are mostly to be cracked under such level of intensity. Moreover, the results indicate that as friction angle increases, probability of sliding between dam and foundation is reduced whereas, increases tensile cracking. Lastly, it is observed that foundation stiffening increases the probability of dam sliding but, reduces the tensile damage in the dam body.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2016년도 학술발표회
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• pp.196-196
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• 2016

Landslide dam failure presents as a severe natural disaster due to its adverse impact to people and property. If the landslide dams failed, the discharge of a huge volume of both water and sediment could result in a catastrophic flood in the downstream area. In most of previous studies, breaching process used to be considered as a constructed dam, rather than as a landslide dam. Their erosion rate was assumed to relate to discharge by a sediment transport equation. However, during surface erosion of landslide dam, the sediment transportation regime is greatly dependent on the slope surface and the sediment concentration in the flow. This study aims to accurately simulate the outflow hydrograph caused by landslide dam by overtopping through a 2D surface flow erosion/deposition model. The lateral erosion velocity in this model was presented as a function of the shear stress on the side wall. The simulated results were then compared and it was coherent with the results obtained from the experiments.

• 한국안전학회지
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• 제35권5호
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• pp.30-38
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• 2020

In order to construct a dam, the diversion facility such as cofferdam and a diversion tunnel should be installed in advance. And size of a cofferdam depends on type of a main dam. According to the Korea Dam Design Standard, if the main dam is a concrete dam, design flood of the cofferdam is 1~2 years flood frequency. This means that overflow of the cofferdam occurs one time for 1 or 2 years, therefore, stability of the cofferdam should be secured against any overflow problem. In this study, failure probability analysis for the concrete cofferdam is performed considering the overflow. First of all, limit state function of the concrete cofferdam is defined for overturning, sliding and base pressure, and upstream water levels are set as El. 501 m, El. 503 m, El. 505 m, El. 507 m. Also, after literature investigation research, probabilistic characteristics of various random variables are determined, the failure probability of the concrete cofferdam is calculated using the Monte Carlo Simulation. As a result of the analysis, when the upstream water level rises, it means overflow, the failure probability increases rapidly. In particular, the failure probability is largest in case of flood loading condition. It is considered that the high upstream water level causes increase of the upstream water pressure and the uplift pressure on the foundation. In addition, among the overturning, the sliding and the base pressure, the overturing is the major cause for the cofferdam failure considering the overflow.

• Computers and Concrete
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• 제12권1호
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• pp.65-77
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• 2013

This paper examines the dynamic response of an arch dam subjected to blast loading. A damage model is developed for three dimensional analysis of arch dams. The modified Drucker-Prager criterion is adopted as the failure criteria of the damage evolution in concrete. Then, Xiluodu arch dam serves as an example to simulate the failure behaviors of structures with the proposed model. The results obtained using the proposed model can reveal the reliability degree of the safe operation level of the high arch dam system as well as the degree of potential failure, providing a reliable basis for risk assessment and risk control.

• 대한토목학회논문집
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• 제5권2호
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• pp.41-50
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• 1985

본(本) 연구(硏究)에서는 earth dam 파괴로 인한 유출수문곡선(流出水文曲線)의 해석(解析)을 실시(實施)하였다. Earth dam의 파괴에 대하여 이제까지 연구(硏究), 조사(調査) 파괴양상 및 저류방정식등(貯溜方程式等) 바탕으로 DBFW(Dam Break Flood Wave) 모형(模型)을 개발(開發)하였고 개발(開發)된 모형(模型)을 Teton과 Buffalo-Creek 댐에 적용(適用)하여 유출수문곡선(流出水文曲線)을 해석(解析)하였는데 그 결과(結果)는 유출수문곡선(流出水文曲線)의 형상(形狀)이나 첨두유량(尖頭流量) 및 첨두발생시간(尖頭發生時間) 등에 대하여 NWS의 조사결과(調査結果)와 매우 작은 편차(偏差)로 일치(一致)하고 있어 본(本) 모형(模型)의 적용성(適用性)을 입증(立證)하였다. 파괴양상이 유출수문곡선(流出水文曲線)에 미치는 영향은 저수지(貯水池)의 지형학적(地形學的) 특성(特性), 파괴부의 형태(形態), 파괴폭 및 파괴지속시간등이 큰 것으로 나타났으며, 국내 earth dam을 지형학적(地形學的) 특성(特性)에 의하여 4가지 type으로 구분(區分)하고 각각에 대한 수위(水位)-수표면적(水表面積) 관계식(關係式)을 도출(導出)한 후 임의의 댐 높이와 파괴지족시간에 대한 첨두유출량(尖頭流出量) 및 유출수문곡선(流出水文曲線) 구할 수 있는 도표(圖表)를 제시(提示)하였다.

• 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.