• 한국농공학회논문집
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• 제55권6호
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• pp.155-165
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• 2013

Recently, geotextile tube method can be widely applied to the river, costal and marine in the construction field, such as embankment, groin, breakwater, dyke structures and so on, in advanced countries of the world. And that has been constructed at the temporary road for incheon, ilsan-bridge construction and coast erosion protection in republic of korea. Geotextile tube is a tube shaped geotextile product and hydraulic pumping filled with dredged soils. In this paper, the numerical analysis was performed to investigate the behavior of geotextile tube with various properties of material character, shape condition, construction pressure and so on. Also, the field test was conducted in order to identify the construction ability of Samangum waterproof embankment using geotextile tube. According to the applied of field test, geotextile tube was 65 m long and 4.0 m diameter. Also, the permeability coefficient and ultimate tensile strength of geotextile tube is $1.6{\times}10^{-1}$ cm/sec and 205.26 kN/m, respectively. As a result of filed test, when filled, geotextile tube does not attain the same as its unfilled theoretical diameter, but may reach approximately of 55 percent of the theoretical diameter. At the time, geotextile tubes were 12.56 m in circumference and filled to a height of about 2.2 m. This paper presents case study on field application and behavior analysis of the saemangum waterproof embankment donggin 1 division construction using geotextile tube.

• 한국산학기술학회논문지
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• 제12권2호
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• pp.927-935
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• 2011

노상층의 지지력을 평가하는 일반적인 방법의 하나로 현장 CBR(California Bearing Ratio) 시험이 널리 이용되고 있다. 그러나 현장 CBR은 시간과 비용이 많이 소모되어 포장층의 강도특성을 단시간에 파악하기에는 어려운 단점이 있다. 최근에는 보다 신속하고 경제적인 방법으로 동적 콘관입시험(Dynamic Cone Penetrometer, DCP)이 많이 이용되고 있다. 본 논문에서는 폐석회를 혼합한 현장모형 노상토에 대하여 현장 CBR 시험과 DCP 시험을 수행하여 현장 지지력을 평가하였으며, 현장 CBR 값과 DCP 지수에 대한 상관관계를 분석하였다. 사용한 폐석회는 인천의 화학공장에서 소다회($Na_2CO_3$)를 생산하는 공정에서 부수적으로 발생하는 부산물이며, 현장시험에서는 현장함수비, 현장밀도, 현장 CBR 시험, DCP 시험을 수행하였다. 시험결과로부터 폐석회 활용도로 노상층에 대한 DCP지수를 제안하였다.

• 한국농공학회논문집
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• 제61권4호
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• pp.63-73
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• 2019

Coastal and fishing facilities are gradually deteriorating in function due to the continual accumulation of soil sediments, which has affected local economic activities. Currently, there are many methods to remove soil sediments, but these methods are either a temporary solution or require a repetitive removal of the soil sediments, which is a huge financial burden for the maintenance of the facilities. To solve these problems, this study proposed a non-power soil cleaning system and evaluated field applicability by carrying out field model tests. The conditions for the evaluation focused on the drainage-elapsed time and drainage-outflow velocity according to the water level change in the water tank. In the field test, silty clay and sand were separately installed, and sedimentation soil removal test was practiced. As a result, the system was verified to have a sufficient outflow velocity for the removal of soil sediments. In addition, a generalization equation that can be used in different regions of the tide was suggested in this study. These results will greatly contribute to removing soil sediments in ports and dike gate facilities on the southwest coast. Since the system is an eco-friendly technology that does not require additional energy, thus it is expected to contribute to maintenance of sustainable facility performance as well as economic effect in the future.

• 한국철도학회논문집
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• 제20권1호
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• pp.64-75
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• 2017

철도궤도 상부 흙노반은 궤광으로부터 전달된 열차하중을 지지하고 분산하는 기능을 갖는다. 성토체의 일반적인 흙노반은 흙재료를 다짐하여 조성하며 차량 반복하중에 의해 공용중 잔류침하가 발생하는 데 일정부분 기여한다. 흙노반의 잔류침하는 회복불가능한 영구변형이어서 궤도틀림 등 궤도 안전성을 크게 저하시킨다. 그럼에도 불구하고 현재까지 흙노반재료에 대한 역학적 시험을 바탕으로 합리적인 잔류침하 관리기준이 제시된 바 없다. 반면에 흙노반의 현장관리 및 판정기준은 강성평가 또는 현장들밀도시험에 의해서만 이루어지고 있어 불합리하다. 본 연구에서는 흙노반이 경험하는 전단응력비(${\tau}/{\tau}_f$)와 구속압(${\sigma}_3$)을 수치해석을 통해 구하고 이를 반영한 실내 흙노반 영구변형시험방법을 제시하였다. 제시된 시험방법을 이용하여 대표적인 철도건설현장 흙노반 재료로 만든 다짐시편에 대하여 반복삼축시험을 실시하였으며 이로부터 향후 잔류침하의 추정에 활용할 수 있는 기본 영구변형예측모델 모델계수를 구속압 및 전단응력비 수준별로 제시할 수 있었다.

• 한국지반공학회논문집
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• 제24권10호
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• pp.33-43
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• 2008

본 연구에서는 현재 운영 중인 경상북도 영천시에 위치한 Y댐에 대하여 댐 축조재료 중 코어죤의 최대전단탄성계수 산정을 위한 합리적인 전단파속도를 산정하기 위하여 시추공을 이용한 크로스홀시험과 다운홀시험을 수행하였고, 지표탐사인 MASW(Multi-channel Analysis of Surface Wave, 다중수의 수진기를 이용한 주파수영역 표면파해석)와 반사법 탄성파탐사를 수행하였다. 현장시험으로부터 코어죤의 심도별 전단파속도를 산정하고 그결과들을 비교 분석하였다. 또한, 현장시험 결과와 Sawada의 경험적 제안식을 비교 분석하였다. 본 연구의 목적은 댐 코어죤의 심도별 전단파속도를 산정하기 위해 수행된 4종류의 현장시험 결과를 비교 분석하고, 시험결과와 경험적 제안식을 비교하여 경험식의 적정성을 판단하고, 기존댐 코어죤의 심도별 전단파속도를 합리적으로 산정하는 방법을 제안하는 데 있다. 시험결과, 측정심도 내(18m 이내)에서 다운홀시험, MASW, 반사법탐사에 의한 코어죤의 심도별 전단파속도 산출 결과는 유사한 결과를 보였으며, MASW와 반사법탐사의 경우에는 심도 30m까지 그 산출 결과가 거의 같은 것으로 나타났다. 기존 댐 로어죤의 심도별 전단파속도를 산출하고자 할 때 운영 중인 댐 코어죤에 시추공을 형성하는 것은 현실적으로 매우 어려운 사안임을 감안한다면 MASW나 반사법탄성파탐사와 같은 지표탐사에 의한 전단파속도 산정이 가장 현실적인 방법일 것으로 판단된다. 현장조사가 여의치 않거나 예비조사의 경우에는 기존의 방법과 같이 Sawada의 경험식을 이용할 수 있는데, 경험식을 이용할 경우 Sawada의 제안식 중 하한값을 적용하는 것이 합리적인 방법일 것으로 판단되었다.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제5B권1호
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• pp.57-62
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• 2005

Grid-connected photovoltaic (PV) systems were installed and monitored at the field demonstration test center (FDTC) in Korea in October 2002. Before long-term field testing of installed PV systems, the performances of PV components were evaluated and compared through short-term performance tests of each of the PV system components such as power conditioning system and PV module under standard test conditions. A data acquisition system has been constructed for measuring and analyzing the performance of PV systems to observe the overall effect of environmental conditions on their operation characteristics. Performances of PV systems have been evaluated and analyzed not only for component perspective (PV array, power conditioning unit) but also for global perspective (system efficiency, capacity factor, electrical power energy) by review of the field test and loss factors of the systems. These results indicate that it is highly imperative to develop an optimum design technology of grid connected PV systems. The objective of this paper is not only to evaluate and analyze the performance of domestic PV systems application through long-term field testing at FDTC but also to develop evaluation, analysis and optimum technology for long-term stability and reliability of grid-connected PV systems in Korea.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.1132-1141
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• 2006

Recently it is difficult to secure sand used in the improvement of soft ground, and so it is necessary to find alternative materials. For this reason many researchers are studying and trying to find new substitute materials. One of the materials is considered as converter slag by wind fracture which is generated in the production of steel manufacture by electric circuit. It is environment friendly since it is a recycled material and economical since it is cheaper than sand. To investigate the applicability of converter slag by wind fracture as the alternative material such as vertical drains, it is necessary to check the drainage effect of this in the field construction. In order to attain an successful design it is important to predict problems encountered in field construction. Accordingly, in this study the laboratory test was executed under different conditions in advance of applying of the field. A total of 4 cases including slag, sand+slag, pack slag and sand as vertical drains was conducted, and at the base of the laboratory test the field test was executed and analyzed.

• 한국정밀공학회지
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• 제20권9호
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• pp.63-69
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• 2003

As increasing underground facilities, more effective management is needed nowadays. It is important to get an accurate information of underground facilities to manage that, so some methods of detecting location - electromagnetic induction method, ground penetration radar method, sound wave method - are used to obtain the information of underground facilities. In this study, a magnetic method to detect underground facilities was developed. In the magnetic method, underground facilities are detected by a detector and the magnetic marker which is a permanent magnet and used to marking the location by attaching underground facilities. A test field was constructed for experiment with the magnetic marker, PVC pipe, and steel pipe under ground 1.5m, and a ferromagnetic detector was used for measurement. Magnetic strengths of the magnetic marker were measured by the detector at each location in the test field, and analyzed by magnetic field analysis tool in the same condition. In the result, the underground pipes of 1.5m below were detectable within the deviation $\pm$0.2m. When For applying this method, it should be considered that ferromagnetic materials around the detector could affect a measured value.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.782-791
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• 2009

This study was carried out the laboratory tests and field plate load test in order to evaluate the reinforcement effect of geocell for road construction. The geocell-reinforced subgrade shows the increment of cohesion and friction angle with comprison of non-reinforced subgrade. In addition, the field plate load test was performed on the geocell-reinforced subgrade to estimate the bearing capacity of soil. The direct shear test was conducted with utilizing a large-scale shear box to evaluate the internal soil friction angle with geocell reinforcement. The number of cells in the geocell system is varied to investigate the effect of soil reinforcement. The theoretical bearing capacity of subgrade soil with and without geocell reinforcement was estimated by using the soil internal friction angle. The field plate load tests were also conducted to estimate the bearing capacity with geocell reinforcement. It is found out that the bearing capacity of geocell-reinforced subgrade gives 2 times higher value than that of unreinforced subgrade soil. In the future, the reinforcement effect of the geocell rigidity and load-balancing effect of the geocells should be evaluated.

• 한국지반환경공학회 논문집
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• 제14권3호
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• pp.13-17
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• 2013

Determination of geotechnical characteristics of soil is either to use the field samples to measure the characteristics of soil through laboratory test or measuring the characteristics directly in the field. Field test can be derived similar value by considering characteristics of site and laboratory test can be confirmed the characteristic of soil by testing with field samples. This article describes relative density as the measure of compaction for cohesionless soils and presents several simple and mathematical relationships to help engineers estimate needed parameters for relative density calculations. The main purpose of this research is to investigate possible correlations between coefficient of uniformity, coefficient of curvature, maximum and minimum void ratio, mean grain size. Results show a linear relationship between the minimum and maximum void ratios and a power function relationship between coefficient of uniformity and the limiting void ratios. Void ratio range, which is the difference between the maximum and minimum void ratios, appeared to be log normally distributed but showed no simple mathematical fit to the data. these results were shown to help engineers estimate needed parameters for relative density calculations.