• The Journal of Engineering Geology
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• v.17 no.3
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• pp.367-379
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• 2007

This study intended to evaluate hydrogeological characteristics in relation to subsurface geology data obtained from borehole, groundwater level, borehole flowmeter test, and field hydraulic tests. The regression equation of groundwater level (Y) versus ground elevation (X) is expressed by Y=0.75X-7.00 with quite high correlation coefficient of 0.78. Relationship between groundwater level and thickness of landfill, alluvium, and weathered zone results in higher correlation of groundwater level (Y) versus natural log value of weathered tone (A) than other correlations, with the regression equation Y= exp(9.974A)-14.155. The result of groundwater flow measurement in the boreholes indicates that groundwater flows towards between south and southwest, and this approximately agree with regional distribution of groundwater levels.

• Journal of Korea Water Resources Association
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• v.30 no.2
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• pp.107-118
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• 1997

The Upper Fenhe Reservoir System studied by KOWACO to supply water to Taiyuan City, capital of Shanxi Province in China, is a very complicated one. Many reservoirs will be connected serially and it will be operated as a multi-purpose and multi-criteria system because several objectives and appraisal functions are taken into account regarding system operation. For reservoirs in the system, the critical system operation objectives are to minimize water shortage and reservoir sediment. Furthermore the reservoir system will be jointed with a large-scale pumping system, namely Yellow River Diversion Project. The water development cost in the Yellow River Diversion Project is much higher than that of reservoir system, and around the year 2020 the diversion volume will be twice of the surface water available in the Upper Fenhe Basin. In this study, an optimization technique for connecting the system of reservoirs and pumping station was developed to solve a conjunctive low River Diversion Project. The developed scheme includes a suggestion on the combining methodology of real reservoir system and pumping system using imaginary reservoir concept for the Yellow River Diversion Project, and practical examples to the minimization problem of the Yellow River diversion satisfying other reservoir operation objectives.

• Korean Journal of Construction Engineering and Management
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• v.15 no.4
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• pp.3-10
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• 2014

As the income level of a country gets improved, people's social, economic, and cultural expectation will grow at the same time. Although the income level of Korea has been remarkably improved, her work-related fatality rate is the highest among OECD countries. Moreover, the rate hasn't been reduced for more than 10 years. This study aims to provide appropriate measures for work-related fatality reduction by comparing the income levels and the work-related fatality rates of countries and by analysing the problems of our worker-oriented accident prevention policy. For the comparison of income level and work-related fatalities, this study suggests income-level incorporated fatality rate, and it turned out that the rate of Korea is the highest among the countries. In order to find out the causes of that result, this study has found that our law enforcement is much weaker than that of UK, which implicates more strict law enforcement policy is needed to improve our work-related safety.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.583-583
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• 2015

근래 게릴라성 호우, 국지성 호우, 짧은 시간에 걸친 집중 호우 등 예측하기 힘든 강우로 인하여 발생하는 피해를 방지하기 위한 방재 사업의 일환으로 각종 연구가 활발히 진행되고 있다. 그러나 원주천 유역, 설마천 유역 등 집중호우로 인해 산사태로 인한 피해가 빈번히 발생, 서울시를 비롯한 전국 도시의 내 외수로 인한 수해피해도 상습적으로 발생하고 있음에도 불구하고 지역 유형별 특성을 반영한 호우피해 대책은 미비한 실정이다. 수재해 사례별 강우특성을 분석하고 유역별 피해저감 대책을 분석하였다. 도시지역의 경우 내 외수로 인한 침수피해가 주로 발생하였고 하천준설, 제방공사, 관로 용량확장, 펌프장 증설 또는 확장을 하는 방법으로 피해를 복구하였다. 농경지의 경우 침수피해나 유실피해가 큰 편이며 2차적으로 오염피해를 유발한다. 우리나라에서는 논으로부터의 영양물질 유출 부하량에 관한 연구는 이미 수행되었으나, 직접적으로 토사유출을 저감하는 적극적인 방법에 대한 연구는 더 수행되어야 할 필요성이 있다고 사료된다. 산지유역의 경우 토석류, 유목등에 의한 피해가 심각하였으며 지금까지의 복구대책으로는 하천의 준설, 사방댐의 설치, 사방댐을 설치한 후 조림(造林)을 설치하여 유사저감 효과를 증대시키는 방법을 포함하여 링네트공법 등 국외에서 개발된 신기술 등이 적용되었다. 대표적 피해유역 유형은 도시, 농경지, 해안, 산지유역으로 분류할 수 있었으며 각 유역별 피해유형을 정리하였다. 앞으로의 연구에서는 기존의 유역별 피해사례 및 강우규모를 바탕으로 최근 강우특성에 적합한 설계기준을 제시하고 특히 유역특성을 반영한 지역 유형별 홍수피해 저감기법에 대해 연구하고자 한다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.12 no.2
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• pp.165-175
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• 2010

Recently, requirement of a long subsea tunnel has increased due to political, economical and social demands such as saving of distribution costs, improvement of traffic convenience, and regional development. Road and railroad tunnel need a shaft for construction and ventilation because of increase of tunnel length. Shaft diameter, lining sectional thickness and rebar quantity have to be determined for design of concrete lining in the shaft. A lot of structural analyses are needed for optimal design of concrete lining considering shaft diameter, load conditions and ground conditions. Design charts are proposed by structural analyses for various conditions in this study. A sectional thickness and rebar quantity can be easily determined using the proposed design charts.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.2
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• pp.103-108
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• 2007

A stress measurement method of structural member using piezoelectric property and electrostatic voltmeter is presented. The electric potentials of the surface of the piezoelectric element, which are proportional to the strain ${\varepsilon}$ on the structural member, are measured by an electrostatic voltmeter during load cycling. The stress ${\sigma}$ is calculated by this strain ${\varepsilon}$. Moreover, a stress distribution measurement tape which can be used for the stress distribution measurement along a specified line on the surface of structural member is developed, and the surface potential was measured by an electric static voltmeter of non-contact type. The applicability of the stress distribution measurement tape is examined through experiments using a notched specimen under cyclic loading. The measured distributions of x, y and xy are compared with those calculated by FEM analysis.

• Journal of the Korea Institute of Building Construction
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• v.16 no.3
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• pp.229-235
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• 2016

In construction field, it used various technique for concrete formwork. Part of them, non-destructive test has been conducted to estimate a compressive strength of concrete easily such as rebound method and ultrasonic pulse velocity method etc. Former research has recommend proposed equation based on experimental data to investigate strength of concrete but it was sometimes deferent actual value of that from in field because of the few of data in case of early strength concrete. In this study, an experiment was conducted to analyze strength properties for early strength concrete using cylinder mold and $1,000mm{\times}1,000mm{\times}200mm$ rectangular specimen. And compressive strength of concrete was tested by non-destructive test, and calculated by the equation proposed former research. As a result, the non-destructive test results showed approximately 70 percent of the failure test value for all conditions, and worse reliability was obtained for high strength concrete samples when the ultrasonic pulse velocity method was used. Based on the scope of this study, the experimental equation for estimating compressive strength of early strength concrete from 24MPa to 60MPa was proposed.

• The Journal of Engineering Geology
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• v.28 no.2
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• pp.277-295
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• 2018

As it has become difficult to secure new water resources through dam construction due to the critical social public opinions on dam construction from 10 years ago, it is necessary to review the existing water resources through the review of existing dams. Accordingly, access methods, such as planning, construction and management, were carried out using technologies already accumulated in relation to the repair and reinforcement of the dam. As a result of the repair and reinforcement, permeation grouting has been performed in many dams, but the establishment of the technology is insufficient so far, and the published paper at home and abroad is extremely rare. In this thesis, low-pressure penetration and grouting reinforcement technologies for the YC dam are analyzed in detail. As a result, penetration grouting has shown that it can be effectively applied to the improvement in the constallability of the core fill-like a YC dam. In addition, the technical details of the experience-proven penetration grouting are given in relation to the injection criteria. It is deemed that the specific analysis data of the Fill Dam penetration grouting technology through this study can be used as useful data for strengthening the repair of Fill Dam and reservoir.

• Journal of Cadastre & Land InformatiX
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• v.48 no.1
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• pp.123-138
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• 2018

To sustainably monitor air pollution in Seoul, the number of Air Pollution Monitoring Station has been gradually increased by Korea's Ministry of Environment. Although particulate matters(PM), one of the pollutants measured at the stations, have an significant influence on human body, the concentration of PM in Korea came in second among 35 OECD member countries. In this study, using the data of PM concentration from the stations, distribution maps of PM10 and PM2.5 concentrations over Seoul were generated, and spatial factors potentially related to PM distribution were investigated. Based on a circumscribed hexagon about a circle in radius of 500 meters created as a basic unit, Seoul was sectionalized and PM concentration map was generated using the interpolation technique of 'inverse distance weighting'. The distributions of PM concentrations were investigated with commuting time by administrative district and the outcome was related with land-use type and volume of traffic. Results from this analysis indicated distribution pattern of PM10 concentration was different from that of PM2.5 by administrative district and time. The distribution of PM concentration was strongly related to not only the size of business and trafficked areas among the land-use type, but also the existence of urban green. Further analysis of the relationship between the PM concentration and detailed land-use and urban green maps can be helpful to identify spatial factors which have an impact on the PM concentration on the regional scale.

• KEPCO Journal on Electric Power and Energy
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• v.6 no.2
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• pp.137-143
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• 2020

The CM247LC, a Ni-based superalloy material used for gas turbine hot gas path parts, is casted using directionally solidified technology to analyze the mechanical properties and microstructures through HIP (Hot Isostatic Pressing) and post-heat treatment, and to derive optimal HIP treatment conditions. The CM247LC material is being researched in various ways as an alternative material for prototyping gas turbine blades. In particular, the blade rotating part is exposed and operated in a high temperature and high-pressure environment, and when damaged, it may cause huge economic losses. Therefore, in order to use the CM247LC material as prototyping materials for gas turbine blades, the reliability of the microstructure and mechanical properties must be verified. In this study, after casting rod test specimens using CM247LC material by directionally solidified technology, after that the specimens were performed by HIP treatment and post-heat treatment to test two HIP conditions designed by KEPCO to derive the possibility of prototyping of CM247LC material and optimization of HIP treatment conditions. Additionally, the properties of CM247LC material were compared to the GTD111DS material using for 1,300℃ class gas turbine blades.