• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.5
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• pp.74-85
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• 2022

The purpose of this paper is to review the applicability of the current standards for the evaluation method of input variables and performance level in seismic performance evaluation by dynamic plastic analysis of the concrete gravity-type dam to which MCE is applied, and to suggest improvements. To this end, a domestic concrete gravity-type dam was selected as a target facility, dynamic plasticity analysis was performed under various conditions, and applicability to input variables such as concrete tensile strength and breaking energy, was reviewed. By analyzing the effect of cracks at the bottom of the gravity dam on the stability of the activity, an improvement plan for the performance level evaluation method required to secure the water storage function was derived. If the proposed improvement plan is applied, it will have the effect of deriving more reasonable evaluation results than the current seismic performance evaluation method to which MCE is applied.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.6
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• pp.1-12
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• 2023

This paper assesses the suitability of existing standards for plastic material models and performance level evaluation methods in seismic performance evaluations of concrete dam piers during Maximum Credible Earthquakes (MCE). Dynamic plastic analysis was conducted to examine the applicability of the plastic material model under various conditions. As a result reveal that when the minimum reinforcement ratio is not met, the average stress-average strain method recommended in current dam seismic performance evaluation guidelines tends to underestimate pier responses compared to the predicted outcomes of dynamic elastic analysis. Consequently, the paper proposes an improvement plan that treats dam piers with an insufficient minimum reinforcement ratio as unreinforced and integrates fracture energy into concrete tensile behavior characteristics for performance level evaluation. Implementing these improvements can lead to more conservative evaluation outcomes compared to current seismic performance evaluation methods.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.470-470
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• 2021

기후변화로 인한 집중호우와 가뭄 등 물 관련 재해가 지속적으로 발생하고 있다. 여름철 강우가 집중되고 하천의 경사가 급한 우리나라의 기상 및 지형학적 조건은 기후변화의 영향과 함께 물관리의 어려움을 가중시키고 있다. 이와 같은 외부적 요인변화에 따라 댐, 보, 제방, 홍수조절지 등과 같은 수자원시설의 안전관리 및 효율적인 운영의 중요성이 높아지고 있다. 특히 「시설물의 안전 및 유지관리에 관한 특별법」 대상인 국가 주요 시설물 가운데 수자원시설의 고령화율이 타시설물에 비해 높아, 체계적인 관리가 필요한 상태이다. 수자원시설의 효율적인 운영 및 유지관리체계를 구축하기 위해서는 첫째, 시설물의 성능평가 제도를 적극적으로 활용하고, 둘째, 국가 주요 시설물의 범위를 확대하며, 셋째, 시설물의 자산관리 체계를 구축할 필요가 있다.

• Journal of Korea Water Resources Association
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• v.51 no.4
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• pp.371-381
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• 2018

Domestic agricultural reservoir dam facilities are difficult to manage water resources because of the in summer rainfall increase due to aging and climate change, it is expected that the dam risk will be large due to the overflow. In this study, author selected study basin in order to evaluate hydrological safety of agricultural reservoir dam facilities. And calculated the probable rainfall, Present PMP, Future PMP considering climate change. Also, author carried quantitative analysis out for increasing rainfall due to climate change, analyze freeboard assessment of agricultural reservoir by calculate flood discharge, reservoir flood routing according to rainfall scenarios. As a result of evaluate hydrological safety of agricultural reservoir dam facilities using Future PMP considering climate change, Gosam, Kumkwang, Miho, Cheongcheon reservoir had the Highest Water Level over the design flood level, it is analyzed that it would be vulnerable to overflow risk.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.66-66
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• 2016

태풍 및 집중호우로 인해 댐과 저수지 등의 붕괴위험이 증가되고 있으며, 실제로 붕괴가 일어나 크고 작은 피해사례가 증가하고 있다. 담수의 목적을 가진 댐과 저수지가 붕괴될 경우 다른 자연재해에 비해 인명 및 재산에 대한 피해가 막대하다. 따라서 국가 및 각 지자체에서 관리하고 있는 댐과 저수지는 안전성 평가 및 비상대처계획 등을 수립하여 만약의 상황에 대해 대비를 하고 있다. 특히 비상대처계획의 경우 댐 붕괴시 상황을 예상하여 홍수파의 전파와 대피로 등을 설정하는 것으로 댐 붕괴상황시 매우 중요한 역할을 한다. 하지만 지금까지의 비상대처계획 수립시 하류부 홍수파 해석은 1차원 모형을 활용하여 범람지역의 산정 및 홍수파에 대한 정보를 획득하였다. 1차원 모형의 경우 빠른 계산시간과 해석을 위한 절차가 간단한 장점이 있으나 건물 및 제내지의 정확한 지형을 반영하지 못하며, 제내지에서의 홍수파 전파양상 등을 나타내지 못하는 단점이 있다. 이에 본 연구에서는 정확한 지형의 반영과 제내지에서의 상세한 홍수파 해석이 가능한 2차원 모형을 이용하여 비상대처계획 수립시 적용성을 검토해보았다. 실제 붕괴사례인 경주 산대저수지 붕괴를 통해 2차원 모형의 정확성을 검증하였으며, 이를 국내 A저수지에 적용하여 비상대처계획도를 작성하였다. 대상저수지의 경우 댐 직하류부에 주거지역 및 홍수파가 넓게 퍼질 수 있는 지형을 가지고 있어 2차원 모형의 장점을 잘 활용할 수 있다고 판단하여 대상 저수지로 선정하였다. 1차원 모형인 DAMBRK 모형과 2차원 모형인 FLO-2D 모형을 사용하여 1 2차원 모형의 댐 붕괴홍수파 해석 결과를 비교하고, 그 결과를 이용한 비상대처계획도를 작성을 하여 비교하였다. 그 결과 기존에 활용되던 비상대처계획도의 단점을 보완하여 정확한 침수범위 및 홍수파 전파양상을 나타낼 수 있는 새로운 비상대처계획도 작성할 수 있었다. 따라서 본 연구를 통해 정확한 지형의 반영이 필요하거나 댐 및 저수지 하류부에 도심지가 위치한 경우 제내지에서의 상세한 홍수파 정보를 제공할 수 있는 비상대처계획도 작성에 기여할 수 있을 것으로 판단된다.

• Journal of Korea Water Resources Association
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• v.48 no.3
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• pp.149-158
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• 2015

It is well known that emergency outlet works have to be provided for the safety of dams. However, concept of emergency outlet works did not applied for the design of the most dams in Korea. Korean design standard for low-level outlet works does not provide enough design criteria which could be used in design of emergency outlet works. In this research, as-built status and hydraulic design criteria of outlet works, such as drawdown rate or hydraulic pressure due to the impounded water depth, were examined. Another relationship between drawdown rate and the dam slope stability was also examined with SEEP model. It was found that 25% reduction of impounded water depth decreases the pressure forces about 50%. Therefore, outlet works should be designed to drawdown properly at the beginning of the emergency. Seepage analysis of dam bodies showed that most of Korean dams could safely stand for 1m/day drawdown rate. Higher drawdown rate could result high discharge so the drawdown rate must be related with the flood risk of downstream. Finally, multi-stage design was recommended that faster discharge for the initial 25% of water depth in 7-10 days than the rest of it in 1-2 months.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.1
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• pp.1-11
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• 2024

The purpose of this paper is to suggest a method for applying a reasonable dam axial seismic load loading method and load-bearing capacity evaluation method in the dynamic analysis of the pier part of a concrete dam to which the seismic force of the collapse prevention level is applied. To this end, the pier part of a concrete dam was selected as a target facility, and the characteristics of the dynamic behavior in the axial direction of the weir dam were analyzed through dynamic analysis applying various weir widths, and 'U.S. The load-bearing capacity evaluation was performed by applying the RC hydraulic structure evaluation technique suggested by the Army Corps, 2007'. As a result of the study, when applying seismic force in the axial direction of the pier part, it is more realistic to assume that the axial direction of the weir part dam behaves as a rigid body and 'U.S. Army Corps, 2007' suggested that the method of reviewing the load-bearing capacity for moment and shear was considered reasonable, so it was concluded that improvement of the current evaluation method was necessary. If the improvement of the research result is applied, it will have the effect of deriving more reasonable evaluation results than the current seismic performance evaluation method using CLE. It is judged that additional research is needed in the future on the torsional moment occurring in the pier part.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.2238-2243
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• 2008

홍수 방류량 하류 도달시간 산정은 댐운영 및 홍수예경보의 기초자료로 인식되고 있어 정확한 유하시간 산정이 필요하다. 수자원공사에서는 댐 방류에 따른 하류도달시간을 댐운영실무편람('06)에 있는 자료를 활용하여 댐 운영에 활용하고 있다. 금강 하류부의 경우 '97년 금강홍수예경보 자료를 활용하고 있으나, 수치모형 결과 자료로 실측에 의한 검증이 이루어지지 않았다. 댐 방류수에 대한 하류도달 시간에 대한 실측 기술을 확보하여 실측을 통한 수치모형의 검증 및 보완 필요하며, 보정된 수치모형을 이용한 홍수도달시간 실시간 예측을 통한 댐운영의 효율성 확보 및 대내외 검증된 결과 제시가 요구되고 있다. 현재 댐 방류에 따른 하류도달 시간에 대한 실측이 요구되고 있으나, 관련 기술에 대한 국내외 개발 및 적용 사례가 전무한 실정으로 본 연구에서는 현장계측과 수치모형을 연계한 신뢰성 높은 도달시간을 분석하는 기술을 개발하고자 하였다. 이를 위해 장구간 내에서 홍수의 흐름과 동일하게 하천에 흘러갈 수 있는 부유물을 개발하였으며, 주야간에 상관없어 주요 계측지점에서 도달시간 산정을 위해 자동 인식될 수 있는 센서기술을 개발하였다. 또한, 인식된 센서를 안정적으로 통신망에 연동하여 실시간 계측이 가능하며, GIS 기반의 원격 모니터링이 가능하도록 시스템을 구성하였다. 나아가. 기존 수치모형에 의존하여 예측된 도달시간 산정방법을 개선하기 위하여 수치모형의 매개변수를 검보정을 위한 시계열 및 지속적으로 자료를 취득하였다. 이러한 센서기술, 모니터링기술, 분석기술을 융합하여 향후 매개변수를 보정한 홍수도달시간 수치모형을 이용하여 신뢰성 높은 예측결과를 홍수예경보 및 댐 운영에 있어 활용함으로써 홍수재해로부터 안전성을 확보하고 물관리의 효율화를 달성할 수 있을 것으로 판단된다.

• Journal of Korea Water Resources Association
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• v.52 no.spc2
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• pp.835-844
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• 2019

This study dealt with a systematic approach for sediment replenishment works which defines the artificial supply of coarse sediment to downstream river channels of dams. That is an increasing practice in Japanese, American and European rivers for the purpose of compensating sediment deficits downstream and rehabilitating geomorphological habitats below dams. We introduced five main objectives of the sediment replenishment, simply from construction of artificial spawning redds for anadromous fish to restoration of fluvial geomorphological process of river system. Then we suggested determination of sediment size distribution and quantity of coarse sediment as well as selecting an effective implementation method in corresponding to specific objectives and local restrictions in the basin, reservoir and river.

• Journal of the Korean GEO-environmental Society
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• v.19 no.12
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• pp.41-46
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• 2018

The wireless sensor network system has the advantage of confirming the behavior of the entire facility by improving the disadvantages of conventional monitoring system. As a result, it is widely proposed as safety diagnosis and measurement of structures, water management systems, and management systems for dam structures. However, there is a lack of research that can evaluate the condition of facilities such as safety at the same time as monitoring. In this study, it is proposed a wireless sensor network system which can evaluate the behavior characteristics of facilities and evaluate the safety status for improving the technical disadvantages on conventional monitoring system. The geotechnical risk factors for the reservoir dam facility were evaluated and the limit values for the risk factors causing the failure of the facility were set. In other words, the system was set up so that the risk factors can be measured and the limit status can be evaluated immediately for each factor. In this study, numerical analysis is carried out for seepage and slope stability analysis using the typical cross section for reservoir dams. The stress-porewater coupling finite difference numerical analysis is performed for establishing the limit displacement for reservoir dam structures. It is developed a system that can estimate the time to reach the critical value by regression analysis using the measured datas.