• Proceedings of the Korean Society for Rock Mechanics Conference
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• 1995.03a
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• pp.48-55
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• 1995

주입공법은 지하공간을 개발할 때 굴착면의 붕괴와 지하수의 유입으로 인한 지하 공동의 불안정성을 방지하고 지반 침하를 최소화하여 지상 구조물에 미치는 피해를 줄이는 목적에 사용되고 있다. 또한 주입공법은 설비가 간단하고 소규모이기 때문에 협소한 장소나 공간에서도 시공할 수 있고 진동 및 소음에 대한 영향이 적기 때문에 공사현장에서 요긴하게 사용되는 공법이다. $^{(1)}$ (중략)

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4A
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• pp.647-657
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• 2006

Probabilistic Risk Assessment considering statistically random variables is performed for the preliminary design of a Cable Stayed Bridge, which is Prestressed Concrete Bridge consisted of cable and plate girders, based on the method of Working Stress Design and Strength Design. Component reliabilities of cables and girders have been evaluated using the response surface of the design variables at the selected critical sections based on the maximum shear, positive and negative moment locations. Response Surface Method (RSM) is successfully applied for reliability analyses for this relatively small probability of failure of the complex structure, which is hard to obtain through Monte-Carlo Simulations. or through First Order Second Moment Method that can not easily calculate the derivative terms of implicit limit state functions. For the analysis of system reliability, parallel resistance system consisting of cables and plate girder is changed into series connection system and the result of system reliability of total structure is presented. As a system reliability, the upper and lower probabilities of failure for the structural system have been evaluated and compared with the suggested prediction method for the combination of failure modes. The suggested prediction method for the combination of failure modes reveals the unexpected combinations of element failures in significantly reduced time and efforts compared with the previous permutation method or system reliability analysis method, which calculates upper and lower bound failure probabilities.

• Journal of the Korean GEO-environmental Society
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• v.8 no.3
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• pp.51-57
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• 2007

In the design of slopes during rainfall, the groundwater level is assumed to be located at the ground surface, based on the change in characteristics of rainfall. In addition, stability investigations are performed for large cut slopes in the design of slopes while standard inclinations specified in the design criteria are applied for the slopes that stability investigations are not performed. In spite of the strengthened criteria of groundwater location, slope failures continuously occur during heavy rainfall, regardless of magnitude of slopes. In order to investigate the cause of the failures, stability investigations have been performed on standard inclination of slopes suggested in the design criteria for both dry and rainfall cases by ground condition in this research. Despite that standard inclination of slopes specified in the design criteria should be stable for both dry and rainfall cases, the results show that standard factor of safety has not been obtained in many cases; more than 50% of total cases for dry cases and more than 65% of total cases for rainfall case. Based on the results, this paper indicates the problems in the current design criteria and proposes the plans for establishment of countermeasure.

• Journal of Korean Society for Geospatial Information Science
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• v.18 no.4
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• pp.71-77
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• 2010

Cut Slope Management System(CSMS) is a systematic maintenance and management system designed to prevent the collapse of cut slopes located along national roads. In order to implement safe road operation system, KICT has started the inventory of cut slopes and developed a cut slope database since 2006. Cut slope database management system using GIS technology and navigation system was developed as a Information Technology application. Through the Cut Slope Navigation System(SLOPE-Navi.), the previously developed database was checked and verified. The converted cut slope inventory data and field investigation data of 28,707 cut slopes were loaded on the navigation map. We consider that the Cut Slope Navigation Management System can be useful as in-situ system, which can be systematic and effective DB management and operation to prevent cut slope collapses and establish a remedial countermeasure as mitigation concerning disasters.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.581-581
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• 2012

경사면의 잠김과 드러남(wetting and drying)에 대한 천수방정식의 수치 실험으로서 그 전선 근처에서 수심이 매우 작은 경우, 수심이 작을 때 2차 정확도를 위한 MUSCL의 적용 여부, 그리고 마찰 적용의 한계 수심 등에 대해 수심경사법(DGM)과 수면경사법(SGM)을 비교 검토하였다. 먼저, 포물선형 융기에서 정상상태의 기준해와 비교하고 하류에서 배수(drain)가 되는 경우를 상정하였다. 그리고 삼각형 바닥 턱을 지나는 댐 붕괴 흐름에 대한 실험의 결과와 비교하였다. 마지막으로 유사난수 발생에 의한 불규칙 바닥 구간을 지나는 가상 댐 붕괴 흐름에 대해 모의하였다. 정상 상태의 잠긴 바닥(wet bed)에 대해 정수 상태에서 SGM의 선평형성(well-balancedness)이 만족되었으나, 흐름이 상류와 사류일 때 각각 DGM과 SGM에서 유량 변동이 있음을 확인하였다. 드러난 바닥(dry bed)으로 흐름이 진행될 때 수심이 음의 값이 되지 않도록 잠김 드러남 전선근처에서 수심이 매우 작아지는 경우($<1{\times}10^{-6}m{\sim}1{\times}10^{-5}m$) 수심을 0으로 강제하고, n이 0.011과 0.04인 경우 수심이 각각 $1{\times}10^{-4}m$와 $1{\times}10^{-2}m$보다 작은 경우 마찰의 적용을 배제하는 것이 불가피하였다. SGM에 의한 MUSCL에서 수심이 $5{\times}10^{-5}m{\sim}5{\times}10^{-2}m$보다 작을 때 1차 정확도로 회귀가 불가피하였으나, DGM에서는 그와 같은 정확도의 훼손이 나타나지 않았다.

• Journal of the Korean Society for Railway
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• v.11 no.2
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• pp.158-164
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• 2008

Abstract Infiltration of rainfall that may lead to reduce resistance force due to reduction of matric suction and to increase driving force due to increase of self weight makes the slope fail. There are many specifications to make slope stable based on factor of safety. Although result of slope stability analysis satisfy the specifications, slope failures triggered by rainfall are frequently occurred in reality because slope stability analysis cannot consider uncertainty of each soil properties. This is why conventional analysis has limitation and development of alternative method is needed. So it is suggested to adopt the reliability analysis rather than design based on factor of safety into designing safer structure. Through the evaluation of handicaps for the factor of safety based design, calculation of soil properties by site investigation, and reliability analysis considering distribution of each soil properties, distribution of failure probability in railway slope is obtained. Then, Risk assessment of slopes in Korean railway is executed from the results. Damage loss and incoming loss are considered as the loss. Using these results, it is possible to make proper countermeasure or efficient maintenance.

• Journal of Korean Society for Geospatial Information Science
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• v.13 no.2 s.32
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• pp.45-50
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• 2005

Recently, slope failures are disastrous when they occur in mountainous area adjoining highways. The accidents associated with Slope failures have increased due to rapid urbanization of mountainous area. Therefore, the inspection of slope is conducted to maintain road safety as well as road function. In this study, we apply to the remedy which is comparing existent description to advanced technology using GIS. we utilize a 3D scanner, one of the advanced method, to generate precise and complete road slope model from expert point of view. In result, we are transferred practical data from external slope stability to hazard slope information. We suggest not only the database but also the method of road risk evaluation based on GIS.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1D
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• pp.169-175
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• 2006

Recently, slope failures are disastrous when they occur in mountainous area adjoining highways. The accidents associated with slope failures have increased due to rapid urbanization of mountainous area. Therefore, the inspection of slope is conducted to maintain road safety as well as road function. In this study, we apply to the remedy which is comparing existent description to advanced technology using GIS. We utilize a Terrestrial LiDAR, one of the advanced method, to generate precise and complete road slope model from expert point of view. In result, we extract hazardous slope information from external measurements referring to the evaluation criteria of external slope stability. We suggest not only the database but also the method of road risk evaluation based on internet GIS.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.21 no.5
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• pp.429-437
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• 2008

In this study the progressive collapse potential of braced frames were investigated using the nonlinear static and dynamic analyses. All of nine different brace types were considered along with a special moment-resisting frame for comparison. According to the pushdown analysis results, most braced frames designed per current design codes satisfied the design guidelines for progressive collapse initiated by loss of a first story mid-column; however most model structures showed brittle failure mode. This was caused by buckling of columns after compressive braces buckled. Among the braced frames considered, the inverted- V type braced frames showed superior ductile behavior during progressive collapse. The nonlinear dynamic analysis results showed that all the braced frame model structures remained in stable condition after sudden removal of a column, and their deflections were less than that of the moment-resisting frame.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.5
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• pp.485-491
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• 2010

Acquisition of information on failure slope, which may cause apprehension of second hand damage, requires acquisition of fast and accurate topographical data and efficient expression in indirect surveying method without accessing as needed. Therefore, in this study, the images on the intended area were photographed through hovering in the air by approaching collapsed road cut slope with the use of unmanned helicopter photography system. As a result of comparing the points observed by no prism total station and the 10 coordinate points analyzed through image analysis, the averages of absolute values were shown to be 0.056m in X axis direction, 0.082m in Y axis direction and 0.066m Z axis direction. In addition, the RMSE of the error for 10 points of test points were 0.015636m in X axis direction, 0.021319m in Y axis direction and 0.018734m in Z axis direction. Therefore, this method can determine the range of slope and longitudinal and cross sections of each slope in dangerous area that cannot be approached in relational image matching method for the terrains of such collapsed cut slope.