• Journal of the Korean Geosynthetics Society
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• v.19 no.2
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• pp.13-21
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• 2020

In Korea, small reservoirs have been constructed for the supply of agricultural water, but most of them have been over 50 years from the year of construction. Aging agricultural reservoirs are being investigated for serious defects such as leaks and movements in slope, which are very vulnerable to safety. Accordingly, grouting methods are used to reinforce aging agricultural reservoirs in Korea. However, cement used as a grouting injection material consumes natural resources and generates a large amount of greenhouse gases during production. In addition, there is a problem that sufficient reinforcement is not made due to various factors such as the injection amount, the compounding ratio, the injection pressure, and etc. Therefore, due to these problems, the development of new materials and methods that can replace the grouting method and cement is required. In order to solve these problems, this study conducted an laboratory test on the surface stabilizer used to secure the stability of road and rail slopes. In addition, the program was analyzed and the reinforcing effect was examined when the surface stabilizer was used as reinforcement material for aging agricultural reservoir. As a result of the laboratory test, when the surface stabilizer is mixed, the increase of cohesion is possible up to 9% and there is no change in the friction angle. The results of the program analysis showed that the 1.0m reinforcement of slopes increased the factor of safety by 1.4 times, making it possible to reinforce the aging agricultural reservoir using surface stabilizers. And as a reinforcement method, it was analyzed that it is most appropriate to reinforce the slope and the bottom of slope simultaneously.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.1
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• pp.93-103
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• 2017

Many countries are interested in the development of the Antarctic area because of the abundant resources and living things of high research value. Korea completed the second Antarctic research station in 2014 and spurring the development of the Antarctic area by constructing runway for the airplanes and a third Antarctic research station. However, frozen soils, unlike typical soils, are sensitive to creep behavior due to the influence of ice and unfrozen water. The creep tests for evaluating creep behaviors on the frozen soils require expensive laboratory equipments and large amount of time. Thus, various empirical models had been developed to describe the unconfined compressive creep behavior of frozen soils. In this study, new analytical creep model on frozen sands was proposed by modifying Ting's Tertiary creep model with a new parameter considering fine contents. Thus, the unconfined compressive creep tests were conducted with the frozen specimens of dense Jumoonjin sand with fine contents of 0, 5, 10 and 15% under various loads at -$5^{\circ}C$, -$10^{\circ}C$ and -$15^{\circ}C$. Consequently, the modified Tertiary creep model with a new parameter for fine contents are not enough for the description of the acutal creep behavior of the frozen sand and new framework should be developed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.6A
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• pp.597-605
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• 2009

The safety of expressway bridges was estimated by checking the external condition rank based on the nondestructive inspection and material test and by measuring load carrying capacity based on the result of load test. Although the load carrying capacity of the bridges was clearly low compared to the design standard, it was examined that many of the bridges have good external condition rank relatively. Also, it can be assured that load carrying capacity shows a considerable difference according to various condition even though the bridges have similar construction year and a structural type. Therefore, this study showed various problems of the current safety measurement of expressway bridges by considering the status of the expressway bridges, external condition rank, and method of safety diagnosis and repair, rehabilitation for maintenance. Based on the existing data of over 400 expressway bridges, the load carrying capacity was analyzed quantitatively considering bridge type, serviced life, design live load, external condition rank and traffic count as variables. The result of this study will be expected to provide the basic information for a reasonable safety assessment of expressway bridge.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.620-624
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• 2009

한국농어촌공사에서 2008년도 환경부 하수처리장 재이용사업으로 선정된 제주특별자치도 서부(판포)하수처리장 농업용수재이용 사업을 위탁받아 사업을 진행하고 있다. 하수처리수를 농업용목적으로 재이용하기 위해서는 농업용수 재이용수질기준에 우선 적합해야하고 작물재배실험 및 수질, 토양, 생태환경 영향 뿐만아니라 공중보건위생 위험도 등 종합적이고 체계적인 연구결과를 바탕으로 적용해야한다. 이를 위해 수자원 프런티어사업단의 "농업용수재이용시스템적용 연구"에서는 하수처리수의 농업용수 재이용과 관련한 종합적인 연구를 통해 농업환경피해를 최소화하고 안전성 확보를 위한 방안을 수립하고 있다. 서부하수처리장은 제주도 한경면 판포리에 위치하여 2007년도에 준공하였고 2008년도부터 본격적으로 가동중이다. 재이용 공급대상 농경지는 처리장의 주변 농경지로 249ha를 대상으로 하고 있으며 사업시행을 위해 타당성 분석, 기본계획 및 실시설계를 시행하였고 2009년 12월까지 시설의 설치 및 시험가동 완료를 목표로 하고 있다. 본 연구에서는 농업용수 재이용사업의 계획 수립을 위해 필요한 분석활동 내용과 안전하게 제주도 하수처리수를 재이용할 수 있는 농업용수 재이용시스템 설계내용을 중심으로 기술하였다. 현재 농촌은 도시화가 전국으로 확산되면서 농촌의 쾌적성은 점차 훼손되었고 하천 호소의 수질이 더욱 악화되고 있다. 또한 농촌지역의 도시화에 따라 하수처리장의 농촌지역에도 늘어가고 있으며 이제는 농촌지역과 도시지역이 구분되지 않고 혼합되어 있는 형태로 발전하고 있기 때문에 과거의 농업활동도 변화되고 있으며, 하천에서 취수하는 용수중에서 농업용수로의 사용이 부적합한 용수가 취수되고 있다. 따라서 하수처리수의 농업용수 재이용시스템과 같이 수처리를 이용한 농업용수의 공급방안이 확대될 것으로 판단된다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.685-693
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• 2011

In the era of energy climate, IGCC technology is one of the powerful solutions for the demands of new energy with low carbon green growth. The present study is conducted to investigate the combustion characteristics of syngas from the coal gasifier to predict problems when it is fed to the gas turbine. Through high and low combustion tests, we understood that hydrogen is the main reason of NOx emission but easily controled by injecting the dilution of nitrogen. CO emission of syngas was comparable with that of methane and pressure fluctuation of syngas was not significant. The data from this study will be used for the optimization of combustion in the Korea first IGCC plant in 2015.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.642-647
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• 2006

Recently Ministry of National Defense is reconstructing old facilities using modular construction method for enhancing soldiers' quality of living. In the future, the use of modular construction method is expected to be increased. But in beginning stage as ROK military facilities that was built by modular was not designed and constructed efficiently, problems for pilot projects need to be analyzed by phases and construction methods should be improved. For the maximized efficiency, design should be made to minimize on-site works, factory automation in an assembly plant should be installed for the better productivity, roads that will be used for transportation should be checked, and joint and connection methods between modules in on-site assembly should be improved for a better quality.

• Journal of the Korean Geosynthetics Society
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• v.11 no.2
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• pp.49-54
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• 2012

The final consolidation settlement is important factor in soft ground improvement because of settlement management and completion time. The compression index, which is slope of primary consolidation curve, is commonly used for the calculation of final consolidation settlement in clay layer. The existing final consolidation settlement is calculated in total consolidation layer that is assumed as one layer. This paper describes analysis result of the acquired settlement, when the consolidation layer is divided as several layer. The consolidation settlement increased according to increase of the divided layer and then it is converged. This result was unrelated to surcharge load. The division effect of layer is very high when the surcharge load is less than the consolidation layer thickness. The division effect of layer is 1.2 to 1.4 in the general surcharge load, and this value can be apply as safety factor in the calculation of final consolidation settlement.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.258-258
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• 2022

물넘이 형식에는 수문과 밸브로 조절할 수 있는 조절형식, 개수로 및 관수로 형식의 자연적으로 수위조절이 되는 비조절형식, 레버린스(Labyrinth), 피아노건반(Piano Key Weir), 사이펀(Siphon) 등의 특수형식으로 구분할 수 있다. 이 중에서 피아노건반 물넘이는 레버린스 물넘이를 피아노건반 모양으로 개량한 것으로 2003년 알제리 Biska 대학의 Quamane 교수에 의해 제안되었다. 제한된 물넘이 폭에 물넘이의 길이를 연장하여 방류능력을 증가시키는 효과를 나타내는 물넘이 형식으로 여수로의 월류수심을 낮게 유지하면서 방류량을 증가시킬 수 있다. 피아노건반 물넘이는 2006년에 프랑스에서 최초로 적용되었으며, 현재까지 약 30여 지역(프랑스, 베트남, 호주 등)의 댐에 적용되었다. 본 연구에서는 국내 저수지를 대상으로 여수로에 피아노건반 물넘이를 적용하여 방류능력과 수리적 안정성 검토를 위해 농어촌연구원 국제융합수리시험센터에서 수리모형실험을 수행하였다. 농어촌연구원은 2018년도에 기존 수리모형실험 시설을 확장하여 가로 250m, 세로 102m의 국내 최대규모의 실내 수리모형실험 시설을 준공하였고, 대형유사순환수로, 고정식 급경사수로, PIV 전용실험수로 등 기능별 7종의 실험수로를 갖추고 있다. 수리실험은 Froude 상사에 의한 축척을 적용하여 모형을 제작하였고, 기존의 수리시설과 하류하천까지 포함하여 70m(L)×20(B)×2m(H) 규모이다. 실험은 유량을 다양하게 변화시키면서 수위-방류량을 검토하였고, PMF 홍수위에서 방류량이 배제 가능한지 검토하였다. 또한, 물넘이의 안정성 검토를 위한 접근유속을 게측하였고, 물넘이를 통해 월류하는 흐름의 유황을 분석하여 수리학적으로 안정한 흐름이 발생하는지 검토하였다.

• Journal of the Korean Geosynthetics Society
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• v.20 no.2
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• pp.23-33
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• 2021

In Korea, many reservoirs have been built for the purpose of solving the food shortage problem and supplying agricultural water. However, the current 75.6% of the reservoirs are in serious aged as more than 50 years have passed since the year of construction. In the case of such an aging reservoir, the stability due to scour and erosion inside the reservoir is very reduced, and if concentrated rainfall due to recent abnormal weather occurs, the aging reservoir may collapse, leading to a lot of damage to property and human life. Accordingly, each agency that manages aging reservoirs uses Ordinary Portland Cement (OPC) as an injection material and applies the grouting method. However, in the case of OPC, it may deteriorate over time and water leakage may occur again. And there are environmental problems such as consumption of natural resources and generation of greenhouse gases. So, there is a need to develop new materials and methods that can replace the OPC. In this study, an laboratory test and analysis were performed on the grout material developed to induce a curing reaction similar to that of OPC by recycling power plant byproduct. In addition, test in the field such as electric resistivity survey, Standard Penetration Test (SPT), and field permeability test were performed to analyzed to reinforcement effect and determine the possibility of using instead of OPC. As a results of the test, in the case of recycled power plant byproduct, the compressive strength was 2.9 to 3.2 times and the deformation modulus was 2.3 to 3.3 times higher, indicating that it is excellent in strength and can be used instead of OPC. And it was analyzed that the N value of the reservoir was increased by 1~2, and the coefficient of permeability (k) decreased to the level of 8.9~42.5%. showing sufficient reinforcing effect in terms of order.

• Journal of the Korea Concrete Institute
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• v.22 no.3
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• pp.297-303
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• 2010

The current encased-concrete deep corrugated steel plate has an arch type plate structure, which is a compressive strength-dominant structure that has a small moment due to its arch shape. Therefore, it increases the strength against compression by adding reinforcements to make concrete-filling spaces for increasing the compressive strength and forming cross sections that contain reinforced concrete. In this study, the safety factor of the new-concept encased-concrete bridge plate member was evaluated by comparing the compressive strength obtained from the compressive tests, flexural tests and the design compressive strength determined by using the Canadian Highway Bridge Design Code (CHBDC, 2003), which is a design standard for the encased-concrete bridge plate structures. The results of the safety factor evaluation using the design compressive strength and the test results showed that the safety factor was well above the appropriate value 2.0, which could be adjudged very conservative. If the safety factor based on this study results is considered and applied to the design, economical construction will be possible due to the reduced cross section and construction cost.