• Journal of Korean Society of Coastal and Ocean Engineers
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• v.30 no.5
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• pp.207-216
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• 2018

This research compared and analyzed safety ratio of slope with Talren97 and SoilWorks based on limit equilibrium analysis and Midas GTS based on finite element analysis. For the analysis variables, there are slope height, berm condition, soil parameter, groundwater level, slope inclination. All of slope stability analysis were performed by dividing into dry season and rainy season. As the result of the analysis of Talren97 and SoilWorks based on same theory, safety ratio of slope shows same value, so there was no difference between the programs. In comparison with limit equilibrium analysis, the result of finite element analysis showed somewhat high ratio of safety and it was higher by about 2.4% averagely. The difference between the result of limit equilibrium analysis and that of finite element analysis is in the range which can ignored in practical work.

• The Journal of Engineering Geology
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• v.19 no.4
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• pp.441-457
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• 2009

This study estimated ultimate load by the determination methods based on ultimate load, yield load and settlement using experimental data from static load tests that applied load to driven piles used in sandy grounds at home and overseas until failure appeared markedly. Estimated ultimate load was normalized with actually measured failure load, and was compared among the determination methods according to the characteristics of pile. In addition, I have identified to the determination methods suitable for estimating ultimate load, and reevaluated the safety factor when determining allowable load. From the results of this study were drawn conclusions as follows. Among ultimate loads estimated by the ultimate-load-based determination methods, the value interpreted by Chin's method tended to overestimate actual measurements, and B. Hansen 80% standard and the stability plot method were considered most reliable as their results were closest to actual measurements. According to the results of this study, in calculating the allowable load, if the safety factor to be applied to failing load obtained by the method of determining extreme load is converted to the safety factor applied to the Standards for Structure Foundation Design, a value larger than 3.0 should be applied except the B. Hansen 90% method, and a value larger than 2.0 should be applied in the methods of determining yield load. In addition, if the safety factor to be applied to load obtained by the settlement standard is converted based on safety factor 3.0 for extreme load, a value smaller than 3.0 should be applied to the total settlement standard and the net settlement standard.

• Journal of the Korean GEO-environmental Society
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• v.6 no.2
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• pp.39-49
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• 2005

In this study, the fifteen month behavior of two geosynthetic reinforced walls which was constructed on the shallow weak ground was measured and analyzed. The walls were backfilled with clayey soil obtained from the construction site nearby, and the safety factors obtained from general limit equilibrium analysis were less than 1.3 in both wall. The measured and analyzed data were horizontal earth pressures, strain of reinforcements, and excess pore water pressures. The used reinforcements were nonwoven geotextile, woven geotextile and geogrid. Although the length of reinforcement was only 30% of wall height and the safety factors of the walls were less than 1.3, the walls were constructed without any problems on the such weak ground. The analysis results showed that the maximum strain of reinforcements were negligible and the strain was between 2.3 and 6.0% according to tensile characteristic of the reinforcements. The excess pore water pressure was not changed due to the rainfall and the horizontal earth pressures in upper and lower part of the walls were larger than the active and the rest pressure.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2003.05a
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• pp.354-359
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• 2003

최근의 재해발생 추이를 보면 1997년 이후 감소하던 재해자 및 사망자는 증가추세에 있다. 2001년도 산업재해통계의 경우를 보면 사망 만인율은 전년동기와 비교하여 감소(2.67$\longrightarrow$12.59)한 반면, 재해자는 11,297명이 늘었고 재해율도 증가하였다. 특히, 50인 미만 소규모 사업장에서 발생한 재해자가 전체 재해자의 69.5%를 점유하며, 전년대췽 전체재해자 증가 11,297명을 상회하는 11,392명이 50인 미만 사업장에서 증가하였다.(중략)

• Journal of the Korean Geotechnical Society
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• v.32 no.6
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• pp.27-40
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• 2016

Conventional warning criteria for landslides due to rainfall in broad regions have limitations, because they did not have proper reflection of topography, forest physiognomy, and unsaturated soil properties, et al. This study suggested a new stability model for unsaturated slope analyses during rainfall, considering rainfall pattern, geomorphological characteristics (slope angle, soil depth), engineering properties of unsaturated soils, and tree surcharge and root reinforcement. Stability analysis not considering root reinforcement and tree surcharge tends to over-predict a factor of safety in unsaturated slopes. Developed slope stability model was used to build database on the factor of safety in unsaturated slopes during rainfall, and it was integrated with GIS to do quantitative risk analysis in landslide risk areas specified in Ulju. Landslide risk areas were located at downstream of the point with sudden drop in safety factor, as well as at regions with low safety factor during rainfall.

• Journal of Korean Tunnelling and Underground Space Association
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• v.7 no.1
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• pp.37-49
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• 2005

In a tunnel, failure of its supports can cause failure of the tunnel. Therefore it is important to estimate safety factor of the tunnel which the failure of its supports is taken into account. In previous studies, supports of tunnels were usually modelled as beam elements. The failure of the supports was decided by comparing the allowable stress and the calculated bending stresses inside the beam elements in estimating safety factor of the tunnel considering the failure of its supports. In this study, it is suggested how to model the supports properly. To this end, supports of a tunnel were modelled by both beam (elastic) elements and continuum (elasto-plastic) elements in two dimensional numerical analyses. Meanwhile, it was analyzed how rock mass class, coefficient of lateral pressure, shotcrete thickness, the existence of rock bolt, and excavation method had an effect on the safety factor of a tunnel.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.3
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• pp.281-287
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• 2011

We consider the uncertainty in the elastic buckling formula for a thin tube. We take into account the measurement uncertainty of Young's modulus and Poisson's ratio and the tolerance of the tube thickness and diameter. Elastic buckling must be prohibited for a thin tube such as a nuclear fuel rod that must satisfy a self-stand criterion. Since the predicted critical buckling pressure overestimated that found in the experiment, the determination of the minimum safety factor is crucial. The uncertainty in each parameter (i.e., Young's modulus, Poisson's ratio, thickness, and diameter) is mutually independent, so the safety factor is evaluated as the sum of the inverse of each uncertainty. We found that the thickness variation greatly affects the uncertainty. The minimum safety factor of a thin tube of Zirconium alloy is evaluated as 1.547 for a thickness of 0.87 mm and 3.487 for a thickness of 0.254 mm.

• Journal of Korean Tunnelling and Underground Space Association
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• v.13 no.2
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• pp.115-131
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• 2011

Recently, considering the aspects of disaster prevention and environmental damage, the construction of a twin tunnel is increasing. When constructing a twin tunnel, the stresses are concentrated at the pillar so that stability of the tunnel is decreased. Since the previous studies on the behavior of a twin tunnel pillar are mainly restricted to the estimation of the tunnel behavior and the analysis of surface settlement, there is a limit to a quantitative stability estimation of the pillar. Therefore, it was quantitatively investigated how the pillar width of a twin tunnel affects its stability. To ensure this end, global tunnel safety factors obtained numerically using shear strength reduction technique, local safety factors of a pillar using the equation that Matsuda et al. suggested, and strength/stress ratios of the pillar were estimated and their results were analyzed for two sections with different rock covers. For a reasonable design of a twin tunnel pillar, it was turned out that strength/stress ratio, the local pillar safety factor, and global tunnel safety factor should be used interrelatedly rather than independently.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.5342-5348
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• 2014

Slope stability analyses were conducted to investigate the limitations of application of the standard inclination of slope and the effects of the berm width on the slope stability. The standard slope inclination could be applied to the basic slope sections that were considered for the analyses, whereas additional slope stability analysis should be performed for the case of considering ground water. A comparison of the factors of safety between the case of installing a berm and the case of letting the grading have an equivalent section area with the case of installing the berm, the factors of safety in the case of installing a berm were greater than those for the case of allowing grading, and the differences between the factors of safety increase with increasing berm width. For all the sections considered in the analyses, the increments of the safety factor were proportional to the width of the berm and those corresponding to the embankment slope and cut slope with a berm width of 7m were 34.5% and 48%, respectively.

• Proceedings of the ESK Conference
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• 1997.04a
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• pp.61-71
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• 1997

큰 사고가 일어날 때마다 '안전관리는 그 무엇보다도 중요하다'라고 강조하지만 우리나라 안전 관리의 현 상황은 열악하다고 할 수밖에 없다. 많은 중소기업이나 심지어 대기업에서도 무의식적 으로 등한시하거나 별로 크게 중요하게 여기는 것 같지는 않은 데, 이것은 현재의 사고발생율과 강도율들을 살펴 보면 누구나 쉽게 공감할 수 있을 것이다. 이러한 맥락에서 이 논문은 안전의 또 하나의 사각지대인 호텔관련업에서의 종사원들은 과연안전에 대하여 어떤 사고방식을 가지고 있으며, 실제 그들의 안전사고는 어떤 것들이며, 안전교육의 효과는 어떠한 가 등을 중점적으로 연구하였다. 실증적 분석에서는 안전관리가 어떻게 이루어 지고 있는 가에 대한 설문조사를 통하여 조사분석하였다. 조사 표본대상으로는 우리나라의 특급 호텔4개와 1개의 콘도미니엄 종사원들을 대상으로 하여 설문지를 배포하여 총 207명에 대한 답변을 토대로 분석을 하였다. 부상내용은 칼종류에 베임이 제일 많았으며, 안전사고의 주원인은 불안전한 자세와 불안전한 행동으로서 이에 대한 교육이 요구된다. 직업과 관련된 육체적 고통으로는 만성피로가 가장 많았다. 그외 구두가 발에 피로감을 주지말 것, 주방의 미끄럼방지, VDT증후군예방, 안전체조 및 구호복창 등의 사항들을 안전사고 예방을 위해 주의해야할 사항으로 요약할 수 있다.