• Journal of the Korean Geotechnical Society
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• v.17 no.3
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• pp.59-68
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• 2001

풍화토 지반에 설치된 그라운드 앵커의 하중전이 현상을 규명하기 위하여 성균관대학교 지반시험장에서 인발시험을 수행하였다. 지반과 구조물을 일체화시키는데 사용하는 앵커는 앵커체와 지반의 마찰력에 의해서 구조물을 지지하는 역할을 하며 앵커의 하중과 변형의 관계를 규명하기 위해서는 앵커의 마찰력 분포의 변화(하중전이)가 중요한 요소가 된다. 하중 재하시 앵커체에 발생하는 하중전이 분포는 앵커의 인발 지지력과 밀접한 관계가 있고 앵커체의 종류(인장형 또는 압축형), 정착장의 길이, 지반 조건 등에 따라 분포 양상이 변하기 때문에 하중전이를 이해하기 위해서는 강선과 그라우트의 하중분포 그리고 앵커 그라우트체와 지반과의 마찰력 분포를 알아야 한다. 앵커의 자유장의 강선에 작용하는 응력, 그라우트체에 작용하는 응력, 그리고 정착장 강선의 응력을 계측하여 강선과 그라우트의 정착응력 및 그라우트와 지반에서의 마찰력 분포를 구함으로써 강선-그라우트-지반의 복합적인 거동에 따른 각 하중 단계마다의 하중전이 분포를 구하였다. 또한 현장시험 결과의 신뢰성 확보를 위하여 수치해석 모델링을 통하여 해석을 수행하여 비교하였다.

• Elastomers and Composites
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• v.35 no.4
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• pp.261-271
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• 2000

Physical properties of NR vulcanizates cured by both sulfur and resole were studied. Cure characteristics of the compounds were also investigated. Two types of resoles with different molecular weight distributions were employed. The scorch time of the NR compound containing the resole with a low molecular weight distribution was shorter than that of the compound containing the resole with a high one. Crosslink densities of the NR vulcanizates with a high resole content after the thermal aging at $95^{\circ}C$ decreased, while that of the vulcanizate without resole after the thermal aging at $95^{\circ}C$ increased. Though crosslink densities of the NR vulcanizates with a high resole content decreased with increasing the aging time, the moduli increased while the tensile strength and tear strength decreased.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.7
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• pp.1295-1305
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• 2000

Status of the contaminated sediments in Lake Paldang was investigated. Sediment samples were taken at 34 points and analyzed in terms of ignition loss, CODer, total P and total N. The contamination level did not show any significant variation with depth of the sediments, which indicated the contaminants were recalcitrant. The type of P in the sediment was analyzed, and the sum of adsorbed P and NAI-P, that can be re-solubilized under the reductive condition, was found to be 20-30% of the total P. From the analysis of the water quality change along with the flowing path, it would be concluded that the effect of the sediments on the water quality is insignificant yet in Lake Paldang. However, long term analysis covering at least four seasons should be continued in order to get a more reliable conclusion. A depth profile map of the sediment in Lake Paldang was provided.

• 한국해양학회지
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• v.29 no.4
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• pp.357-365
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• 1994

The sediments on the continental shelf off the west coast (middle part) of Korea are divided into northern sandy deposits and southern muddy sediments, respectively. The sandy sediments consist dominantly of quartz and feldspar grains, representing mature-stage sediment in composition. Further-more, the presence of iron-stained quartz grain and glauconite does indicate that the sediments are similar to the relict sediments on the outer shelf of Yellow Sea and East China Sea. These sandy sediments are interpreted as a basal sands that were deposited during the transgression period due to sea-level rise after to last glacial maximum (LGM). The tidal deposits in the Namyang Bay, the west coast of Korea are divided vertically into the upper layer of muddy sediments and the lower layer of sandy sediments. the upper layer sediments contain abundant rock fragments, and are interpreted as the modern tetragenous sediments. The lower layer sediments, on the other hand, are rich in quartz and feldspar grains, representing high index of sediment maturity ratio. the lower layer sandy deposits show the presence of iron-stained.

• The Journal of Engineering Geology
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• v.32 no.2
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• pp.241-255
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• 2022

In this study, sieve analysis testing was performed on weathered granite soil from Yecheon (eastern South Korea) before and after water washing in accordance with the sieve analysis regulations of KS F 2302. The changes in particle separation and particle size distribution after washing with water were analyzed. Image analysis using an optical microscope revealed that soil particles were separated into smaller particles by water washing. The change in the particle size distribution curve was assessed using five index values. The increase in the fine particle fraction (<0.075 mm) was 13.67%, the increase in the 0.075-0.25 mm fraction was 19.44%, and the mean particle diameter (D₅₀) decreased by 0.663 mm. In addition, the maximum passage width (B_M) of the particle size distribution curve increased by 21.08% for the #30 sieve, and the moving area (A) of the particle size distribution curve was 69.28%·mm. These results suggest that washing with water is an effective way to prevent underestimation of the fine particle content in soil.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.75-79
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• 2005

GSSHA(Gridded Surface Subsurface Hydrologic Analysis) 모형은 미 공병단 연구개발센터(USACE ERDC; US Army Corps of Engineers Engineering Research and Development Center)체서 개발된 물리적인 개념의 공간 분포형(PBSD; Physically Based Spatially Distributed) 수문모형으로, CASC2D 모형(Ogden 와 Julien, 2002; Downer 등, 2002)을 개선, 확장한 모형이다. GSSHA 모형의 실행에는 Brigham Young 대학의 컴퓨터그래픽공학연구실에 의해 개발된 미 국방성 WMS(Watershed Modeling System) 인터페이스를 사용하며, 이를 통해 많은 입력과 출력조건을 가지는 분포형 모형의 복잡한 모의 과정을 효과적으로 처리할 수 있다. 본 연구에서는 GSSHA 모형을 이용하여 경안천 유역의 물순환 양상을 분석하였다. GSSHA 모형은 유역을 균일한 유한 차분 격자로 나누어 각각의 격자를 기본 단위로 모의한다. 모형의 주요 모의 모듈은 강우 분포, 융설, 차단, 침투, 증발산, 지표면 저류, 2차원 표면류 추적, 1차원 하도 추적, 불포화 층 모의, 2차원 포화 지하 대수층 흐름, 지표면 유사 침식, 하천 유사 추적 등이 포함된다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.10a
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• pp.617-619
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• 2022

An embedded fiber-optic sensor was manufactured using 3D printing technology for distributed structural monitoring. Strain distribution of the embedded sensor was measured by the optical frequency domain reflectometry, and real-time data visualization for the embedded sensor model was demonstrated.

• Journal of the Korean Association of Geographic Information Studies
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• v.20 no.2
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• pp.32-46
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• 2017

Recent rapid urban expansion and crowding of various industrial facilities has affected the features of a significant part of downtown area, resulting in areas having buildings with a wide range of height and the foothills. To compute a velocity pressure exposure coefficient, namely the design wind speed factor, this study defines ground surface roughness by utilizing concentration analysis for the height of each building. After obtaining spatial data by extracting a building layer from digital maps, the study area was partitioned for the concentration analysis and to allow investigation of the frequency distribution of building heights. Concentration analysis by building height was determined with the Variation-to-Means Ratio (VMR) and Poisson distribution analysis using a buildings distribution chart, with statistical significance determined using Chi-square verification. Applying geographic information systems (GIS) with the architectural information made it possible to estimate a velocity pressure exposure coefficient factor more quantitatively and objectively, by including geographic features, as compared to current methods. Thus, this method is expected to eliminate inaccuracies that arise when building designers calculate the velocity pressure exposure coefficient in subjective way, and to help increase the wind resistance of buildings in a more logical and cost-effective way.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.1
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• pp.138-149
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• 2014

This study proposes an estimation method of strain distribution for multi-span steel beam structure under unspecific loading conditions. The estimation method in this paper employs the curve fitting using the least square method from measured strain data, not analytical method. To verify the proposed estimation method, a static loading test for multi-span steel beam on which distributed and concentrated loads act was conducted. The strain data for verification was measured by FBG sensors that have multiplexing technology. The analysis of the accuracy of strain estimation for distributed and concentrated loads and the errors by considering the number of measured points used in the estimation were conducted. In the maximum strain points, the strains could be estimated with the errors of 5.89% (loading step 1) and 6.26% (loading step 2). In case of decreasing the number of sensors, it was also confirmed that the errors increased (0.26~0.37%). Through the curve fitting method, it is possible to estimate the strain distribution (maximum strains and their locations) of multi-span beam for unspecific loads and go over the limit of the analytical estimation method which is suitable for specific distributed loads.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.8 no.3
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• pp.340-348
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• 2003

Sedimentological investigations on surface and suspended sediments were performed in Kwangyang Bay of the middle South Sea in order to reveal recent changes in depositional environments concerning anthropogenic influence. A variety of coastal developments caused the texture of the surface sediments to become distinctively finer, particularly in the southwestern part of the bay. Accordingly, the westward lining sedimentary facies was somewhat simplified from triple-mode distribution to the dual-mode one by the construction of POSCO. This east-west distribution to the sedimentary facies has recently graded into the north-south distribution by further construction of other industrial complexes including Kwangyang Port. The prominent textural changes in surface sediments are most likely associated with weakening of tidal currents related to the developments which is anticipated to be .still continued. The distribution and flux estimation of suspended sediments suggest a noticeable import of fine particles into the bay predominantly through a northern entrance rather than the southern entrance. The movements of suspended sediments in the water level near the seabed prevailed over those of the mid and surficial levels.