• Journal of the Korean Geosynthetics Society
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• v.17 no.1
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• pp.45-54
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• 2018

In this study, numerical analysis is performed to determine highly influential factors that increase the possibility of asphalt road collapse due to cavity underneath the road. The considered influence factors on road collapse due to underground cavity were the asphalt layer thickness, the cover depth, the cavity width, and the cavity height. The concentrated load and uniform distributed pressure were applied on the top surface of asphalt pavement layers with different shape of cavity and asphalt thickness. For each analysis case of given cavity and asphalt thickness, failure load was analyzed under displacement controlled condition. Based on the analyzed failure loads, the applicability of the cavity management system developed by Seoul city was evaluated. As a result of the analysis, the effect of cavity height on road collapse was not significant while the other factors considerably influenced road collapse. Consequently, degree of road collapse susceptibility should be classified by failure load rather than by the condition of existing cavity.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.2
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• pp.113-120
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• 2017

HCP(Half Cell Potential) method has been widely used since it is recognized as a efficient NDT(Non Destructive Technique) for corrosion detection. This work is for an evaluation of relation between corrosion amount and measured HCP in dried condition through ICM(Impressed Current Method) for accelerating corrosion. For the work, cement mortar specimens with three w/c ratios and four cover depths are prepared, and corrosion test based on ICM is performed for 6 hours, 18 hour, and 42 hours with constant 20V of electrical charge, respectively. From the test, corrosion amount increases with reduced cover depth, increasing w/c ratio, and extended corrosion period, where corrosion amount is evaluated to linearly increases with measured HCP in dried condition. In order to evaluate corrosion amount through measured HCP, the measured HCP level is firstly determined and then corrosion amount is to be compared with measured HCP, which is evaluated to be more reasonable with higher C.O.V.

• International Journal of Highway Engineering
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• v.12 no.4
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• pp.187-196
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• 2010

The purpose of this study is to develop the calibration method for temperature effects to improve the accuracy of the Weigh-In-Motion(WIM) system for collecting long-term truck weight data. WIM system was installed at a location where the truck traffic volume is high and weight data has been collected from January 2010. In this study, as a calibration measure, the first axle weight of Truck Type 10, the semi tractor-trailer is used based on the fact that the first axle weight is relatively constant, independent of the cargo weight. From this fact, calibration equations are developed from the relationship between the axle weight and the temperature(daily mean, maximum and minimum). Analysis on calibrated weight data shows adequacy of the proposed calibration method. Results of this study can be used to improve the accuracy of the WIM system and to carry out more rational design of pavement and bridge structures.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.613-619
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• 2009

과거의 용수개발은 단위시설 또는 단위사업별 중심의 양적 확대개발 위주로 추진하여 수리시설간 수자원을 효율적으로 활용할 수 있는 용수공급체계가 미흡하였다. 수리시설의 양적 확대개발 위주의 추진결과 '03년도 총 수리시설수인 68,018개소 중 관개면적 50ha이상의 주 수원공은 1,888개소로서 전체수리시설의 2.8%를 차지하여 비합리적인 공급불균형 현상이 발생하여 체계적인 급수관리가 이루어지지 못하는 문제가 발생하였다. 또한 기존의 공급체계는 논 용수중심에서 식생활 변화로 인한 밭작물 수요증가로 용수이용 패턴이 변하고 있다. 더욱이 농촌지역의 생활환경 개선이 요구됨에 따라 생활용수, 공업용수, 환경용수 등 농촌지역에 과거와는 다른 형태의 용수수요가 발생하고 있다. 하지만 농촌지역의 수자원은 한정되어 있고 환경파괴 및 적지부족 등의 이유로 신규 수자원개발이 불가능한 사회여건이 지속되어 있어 많은 문제점이 나타나고 있어 균형적인 농촌발전과 건전한 농촌지역조성을 위해서는 새로운 대안이 제시되어야 하는 시점이다. 본 연구에서는 그 대안으로 부각되고 있는 농업용저수지 재개발에 대하여 사업의 우선순위를 합리적으로 결정할 수 있는 의사결정시스템의 개발을 목적으로 하고 있다. 기존 문헌을 고찰하면 개발우선순위는 과학적 논리보다는 정치적, 사회적 논리가 의사결정에 중요한 역할을 하였으나 의사결정시스템의 제공을 통해 정책결정자가 과학적이고 합리적인 논리에 따라 사업개발의 우선순위를 결정할 수 있을 것으로 기대한다. 본 연구에서는 재개발 의사결정에 필요한 지형적, 사회적, 환경적 요인을 지수화 하는 방법을 고찰하였고, 우선순위를 산정에 필요한 수치지도, 저수지 관련 자료의 작성과 지형정보(GIS)를 구축하였다. 우선순위 대상저수지의 선정은 기존문헌과 수계 및 용량 등을 고찰하여 79개로 우선 선별하였다.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.485-490
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• 2003

Nowadays the rapid change in construction environment getting more globalized and complicated has caused lots of unexpected risks from inside and out of the country, so more sophisticated construction management strategies are being strongly needed. This paper suggests a risk management model with which we can estimate the appropriate contingency by quantifying the amount of probable risks immanent in large construction projects, which have a high degree of uncertainty in the anticipation of the total construction cost. To develop the model, the risk factors that make cost variations are elicited based on the real data of the contingencies assigned to the past projects. Furthermore, the influential relationship of risk factors is structured by applying the CRM(Cost Risk Model) which is the synthetic model of Monte Carlo Simulation, Influence Diagram and Decision Tree. The ultimate outcome of this research can by validated by tile case study with a large construction project performed.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.577-580
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• 2003

The purpose of this study was to make a database model for financial feasibility study of buildings offered for sale which is helpful for improvement of business ability in construction and confidence of a project from a related participant. At first, we studied several thesis and met some professionalist which work for construction and did a first survey for examining latest situation of a feasibility study in construction. As a result, even though feasibility study is important, factors for information management wasn't systemized. So we did a second survey for fixing Factors of the database model. The database model was composed of the factors that we got from the second survey. ER(Entity-Relationship) analysis was used to making it. We expect thar we can get more reasonable information to study financial feasibility study and can diminish risks of project through the database model. So the result of this study was to make a database model for more reasonable financial feasibility study of building offered for sale.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.3
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• pp.565-572
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• 1994

Consolidation behavior on soft clay was investigated by using one- and two-dimensional analysis based on original and modified one dimensional consolidation theory. For the analytical model, the embankment was simulated by applying single- or multi-surcharge loading to the surface of soft clay. Based on the results obtained, it was found that the predicted settlement by one dimensional consolidation theory was most of the time higher than the observed one at the mid- and especially lateral-zone of embankment. When compared with two dimensional analysis, the result of modified one dimensional consolidation analysis showed almost similar trend to the observed one. There fore even in case where proper selection of soil parameters, one dimensional consolidation theory like as modified one dimensional consolidation theory could be suggested due to its convenience.

• Journal of the Korean Institute of Gas
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• v.18 no.3
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• pp.44-52
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• 2014

Small petrol stations have great potential for a wide distribution in metropolitan area in which the land value possesses primary installation cost of the facility. The objective of the present study is to propose appropriate facility regulations of small petrol stations in Korea that can be popularly installed in the future in terms of securing safety in addition to serviceability. The hazard analysis and damage prediction from the possible fire and explosion accidents were performed using a software, PHAST v.6.5. As essential components of the facility regulations proposed in this study, the regulations about the refueling lot, maximum capacity of underground tank, location of fixed refueling facilities, height of firewall for small petrol stations were subsequently compared with those for regular-sized petrol stations.

• Journal of the Korean School Mathematics Society
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• v.12 no.3
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• pp.319-345
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• 2009

Nowadays the researches on the reading materials about Mathematics are emphasized and quitely active. But most researches have just proposed the lists of books or materials of the reading activities in Mathematics. Therefore we choose the subject for this study as the analysis of the characteristic attitudes about Mathematics for 3-leveled (high, middle, low) high-school students who have studied Mathematics using the reading activities. After the applications of reading activities for leveled students, we have the following results. For the low-leveled students, the high-leveled(=difficult to understand) reading materials may loose the confidence and interest about Mathematics. The appropriate reading materials for leveled students will increase the interest and change the attitude about Mathematics. We expect that the reading activities in Mathematics extend the logical and rational thinking power that our society has required.

• Journal of Korean Tunnelling and Underground Space Association
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• v.18 no.6
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• pp.525-533
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• 2016

The purpose of current tunnel maintenance system in South Korea is safety-based maintenance system for accident prevention, So it is difficult to conduct a strategic maintenance. The development of a new maintenance system can lead to effective investment of limited financial and it's effort is still in progress. In this study, to develop a performance-based assessment method, indexes for assessment are derived taking into account the safety, durability and serviceability. The indexes for performance-based assessment were selected by a literature analysis and a delphi survey. Then the importance among indexes were calculated by the AHP analysis.