• 한국터널공학회:학술대회논문집
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• 한국터널공학회 2005년도 학술발표회 논문집
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• pp.262-269
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• 2005

The priority order about a rational repair and reinforcement is generally decided by subjective decision of engineer. An appearance investigation by tunnel scanner that is widely used in foreign nation was carried out to decide about a rational repair and reinforcement through systematic and objective analysis in box and NATM tunnel. We have decided on the order of priority of an rational repair and reinforcement through the crack density analysis by span, distance and location with the result of tunnel scanner.

• 한국지반공학회논문집
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• 제16권6호
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• pp.127-139
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• 2000

In the study, an expert system was developed to predict the safety of tunnel and select proper tunnel reinforcement system using fuzzy quantification theory and fuzzy inference rule based on tunnel information database, For this development, many tunnelling sites were investigated and the applied countermeasures were studied after building tunnel database. There will be benefit for the deciding tunnel reinforcement method in the case of poor ground condition. The expert system developed in the study has two main parts, pre-module and post-module. Pre-module is used to decide input items of tunnel information based on the tunnel face mapping information which can be easily obtained in in-situ site. Then, using fuzzy quantification theory II, fuzzy membership function is composed and tunnel safety level is inferred through this membership function. Post-module is used to infer the applicability of each reinforcement methods according to the face level. The result of the predicted reinforcement system level was similar to measured ones. In-situ data were obtained in three tunnel sites including subway tunnel under Han River. Therefore, this system will be helpful to make the mose of in-situ data available and suggest proper applicability of tunnel reinforcement system to development more resonable tunnel support method without dependance of some experienced experts opinions.

• 한국농공학회지
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• 제37권5호
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• pp.101-110
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• 1995

The use of geotextile as reinforced materials in Soil structures has become widespread throughout the world. Geotextile reinforcement has been used in retaining walls, slope of embankment and especially soft foundation, etc. In the past, however, its design and construction have been performed empirically. In this study, to investigate of the effect of geotextiles reinforced slope of the embankment on a very soft foundation, a limit equilibrium analysis program calculating the safety factor of embankment on very soft foundation was developed. The study was focussed on such factors as type of geotextile, tensile strength, amount of reinforcement, and inclination of embankment. And the 4imit equilibrium analysis program was written on the basis of Low's slope stability theory with some modification. The following conclusions were drawn from this study. (1) The orientation of reinforcement can be assumed either horizontal or tangential to the slip circle. The factor of safety with tangential reinforcement is larger than that with the horizontal reinforcement. (2) In general, the factor of safety increases, as the slope reduces. However, it is preferable to use geotextiles with higher tensile strength rather than to reduce the slope of the embankment, because it is difficult to adjust the slope as desired. (3) The factor of safety obtained by numerical computation is affected only by the tensile strength, but not by the type of the geotextile.

• 지질공학
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• 제31권3호
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• pp.343-355
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• 2021

농업용저수지는 농업용수를 공급함과 동시에 수해효과 및 휴식터를 제공함으로써 인간의 편의성을 추구하지만 노후 저수지 및 지진으로 인한 피해가 발생될 수 있으며 이에 따른 예방이 중요하다. 제방의 안전성은 제방을 구성하는 세분화된 재료의 토양 매개변수 값과 같은 현장재료 특성에 의해 영향을 받지만 정밀안전진단이나 일반 문헌값이 전용되기 때문에 최종제반의 안전인자를 물질적 특성만으로 판단하기에는 한계가 있다. 안전요인은 물리적 특성값과 제방 형태에 의의 결정되며 안전 요인에 상당한 영향을 미치기 때문에 보강된 횡단면을 검토할 때 정확한 사색이 필요하다. 따라서 본 연구에서는 GEP-SLOPE 프로그램을 활용하여 전남 고흥근 '◯◯저수지' 내진설계 시 합리적이고 경제적인 보강교차로 사례를 분석함으로써 반복적인 검토를 통해 보강교차로에 대한 합리적 경제적 설계가 가능하도록 분석하였다. 제방의 1, 2, 3차 내진보강을 감소하여 분석한 결과, 3차 보강단면에서도 상류, 하류사면 모두 설계기준 1.20 이상을 얻음으로써 1. 2차에 비해 현저히 적은 보강물 보강물량으로도 안전율 확보가 되는 것을 확인하였다. 또한 제반의 내진보강 단면 형상을 결정할 때 사면의 상부측, 사면전체에 사석을 보강하는 것 보다 하부측에만 보강하는 형상이 단면보강을 최소화 시키며 경제적인 것을 확인하였다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 봄 학술논문 발표대회
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• pp.87-88
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• 2022

For an earthquake-safe urban environment, the Republic of Korea conducts seismic performance evaluation in accordance with laws and guidelines to assign safety ratings and implement necessary management measures such as repairs and reinforcements. In the seismic performance evaluation result, structures lacking in preparation for earthquakes are prioritized and classified into measures such as repair, reinforcement, or careful observation to respond to physical risks such as earthquakes. Such repair and reinforcement work is not a one-time thing, but it is necessary to further enhance the effect through continuous follow-up observation. In this study, the location of the vertical and horizontal displacement measuring part of the construction part is displayed so that the post-construction status of the reinforcement construction part can be visually checked by identifying the problems in the process of post-monitoring in 2022 for the maintenance and reinforcement work of local governments' public facilities carried out in 2021. We propose a plan to institutionalize the installation of, inspection tools, and crack gauges at certain locations in the construction department, and to have facility managers periodically inspect and manage them with a smartphone program or the 'Facility Autonomous Safety Inspection' app.

• Nuclear Engineering and Technology
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• 제55권12호
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• pp.4527-4542
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• 2023

The present microbial reinforcement of rock and soil exhibits limitations, such as uneven reinforcement effectiveness and low calcium carbonate generation rate, resulting in limited solidification strength. This study introduces electroosmosis as a standard microbial grouting reinforcement technique and investigates its solidification effects on microbial-reinforced uranium tailings. The most effective electroosmosis effect on uranium tailings occurs under a potential gradient of 1.25 V/cm. The findings indicate that a weak electric field can effectively promote microbial growth and biological activity and accelerate bacterial metabolism. The largest calcium carbonate production occurred under the gradient of 0.5 V/cm, featuring a good crystal combination and the best cementation effect. Staged electroosmosis and electrode conversion efficiently drive the migration of anions and cations. Under electroosmosis, the cohesion of uranium tailings reinforced by microorganisms increased by 37.3% and 64.8% compared to those reinforced by common microorganisms and undisturbed uranium tailings, respectively. The internal friction angle is also improved, significantly enhancing the uniformity of reinforcement and a denser and stronger microscopic structure. This research demonstrates that MICP technology enhances the solidification effects and uniformity of uranium tailings, providing a novel approach to maintaining the safety and stability of uranium tailings dams.

• 자동차안전학회지
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• 제10권3호
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• pp.13-19
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• 2018

This research is to optimize Single-Piece Side otr reinforcement using Hot-stamping and to strengthen weak regions on Single-Piece Side otr reinforcement. As a consequence, the weight and the number of parts were reduced and resulting in improvement of impact and stiffness performance when compared to multi-piece construction.

• Geomechanics and Engineering
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• 제28권2호
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• pp.145-155
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• 2022

Safety is a most important parameters in underground railway transportation; Also stability of underground tunnel is very important in tunneling engineering. Design of a reliable support system requires an evaluation of both ground demand and support capacity. Iran's traditional railway tunnels are mainly supported with masonry structures or unsupported in high quality rock masses. A decrease in rock mass quality due to changes in groundwater regime creep and fatigue in rock and similar phenomena causes tunnel safety to decrease during time. The case study is an old tunnel in Iran, called "Keshvar"; it is more than 50 years old railway organization. In operating this Tunnel, until the several problems came up based on stability and leaking water. The goal of study is evaluation of the various reinforcement systems for supporting of the tunnel. The optimal selection of the reinforcement system is examined using TOPSIS Fuzzy method in light of the looming and available uncertainties. Several factors such as; the tunnel span, maintenance, drainage, sealing, ventilation, cost and safety were based to choose the method and system of designing. Therefore, by identifying these parameters, an optimal reinforcement system was selected and introduced. Based on optimization system for analysis, it is revealed that the systematic rock bolts and shotcrete protection had a most appropriate result for these kind of tunnel in Iran.

• 한국산업융합학회 논문집
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• 제23권4_2호
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• pp.603-609
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• 2020

The purpose of this study is to research dampers, which are applied mainly to buildings adjacent to the coast, such as nuclear facilities, and used for ventilation and can safely protect lives and equipment in emergency situations. Comparing the equivalent stress for three models with hinge reinforcement and support reinforcement based on the early design model for Damper, in the Base model, the highest stress occurred in the part of hinge, especially in the centrally mounted hinge, and after reinforced the hinge, it was occurred in the rear support. For models reinforced hinges and supports, it is considered that reinforcement for stiffness will be required in the future as it entered within the range of allowable stress. For the safety factor distribution, the minimum safety ratio was sufficiently secured at least 1 and was high at the edge of the Damper frame and the Blade. As the hinge was reinforced, the safety factor distribution of Blade was increased, and it was verified that the safety factor was secured through the support reinforcement.

• 한국안전학회지
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• 제37권6호
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• pp.60-70
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• 2022

This paper proposes an optimal design method of a seismic reinforcement system for the seismic performance of adjacent asymmetric-stiffness structures with viscous dampers. The first method considers plan asymmetry for efficient seismic reinforcement, and evaluates the seismic performance of optimal design applied to two cases of modeling: adjacent stiffness-asymmetric structures and adjacent stiffness-symmetric structures. The second method considers the response of asymmetric structures to derive the optimal objective function, and evaluates seismic efficiency of the objective function applied to two cases of responses: horizontal displacement and torsion. Numerical analyses are conducted on 7- and 10-story structures with a uni-asymmetric-stiffness plan using six cases of historic earthquakes, normalized to 0.4g. The results indicate that the seismic performance is excellent as modeled by adjacent asymmetric-stiffness structures and how much horizontal displacement is applied as the objective function.