• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.2
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• pp.119-131
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• 2021

In general, the stress is concentrated on the pillar of very near parallel tunnel (VNPT), and the pillar has been reinforced by using steel-wires to maintain the stability of the tunnel. However, since the strength of the pillar decreases in the soil layer, the reinforcing pillar with the steel-wires is insufficient for tunnel stability. In this study, the laboratory tunnel experiment was conducted to examine the reinforcement effect for a new method, of which the pillar of VNPT is strengthened by using steel-pipes. As a result, against overburden stress, the bearing capacity of the steel-pipe reinforcement was 22% greater than that of the steel-wire reinforcement. In using the Particle Image Velocimetry method, the analysis shows that the steel-pipe reinforcement forms a more favorable condition of which uniformly the overburden load acts on the VNPT and the pillar than the steel-wire reinforcement. Based on the results, the steel-pipe reinforcement is expected to bring a more positive effect on tunnel stability than the steel-wire reinforcement.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2011.10a
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• pp.533-534
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• 2011

• Nuclear industry
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• v.35 no.3
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• pp.35-39
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• 2015

• Proceedings of the Korean Fiber Society Conference
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• 1999.10a
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• pp.263-266
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• 1999

• Proceedings of the Korean Fiber Society Conference
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• 1991.06b
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• pp.40-40
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• 1991

• Proceedings of the Korean Fiber Society Conference
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• 1995.10a
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• pp.20-20
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• 1995

• Journal of the Korean Geosynthetics Society
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• v.23 no.3
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• pp.23-30
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• 2024

According to the method of settling the construction structure on the ground to keep the structure safe, the ground anchor method is divided into a load-distributing anchor and a general anchor. Recently, the application of load-distributed anchors, which show a large degree of recognition by anchors, is increasing in the field, but the problem of field applicability is also caused. The load-distributed anchor fixes the tensile force to each section of the lecture line and applies it, causing a problem of asymmetric loads in which the maximum tensile force size of each settlement site differs due to the length difference of the anchor body. Therefore, in this study, as a quality management method according to the asymmetric load of anchors, a mono-type load cell that can measure the load for each lecture line of a load-distributed anchor was developed, and the field applicability was analyzed by comparing and analyzing the measurement results of the existing multi-type load cell and mono-type load cell. As a result of the study, the multi-type load cell had no choice but to estimate the working load for each inner body, so it was impossible for the load-distributed anchor to manage it according to the generation of asymmetric loads for each lecture line. However, in the case of a mono-type load cell the load was measured for each inner body and for each lecture line, regardless of ground conditions and construction conditions, and thus the load value was measured for each lecture line, enabling safety management and construction management according to the occurrence of asymmetric loads.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.2
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• pp.43-63
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• 2023

With the concentration of the population in the city center and the saturation of the structures on the ground, the development of the underground structures becomes important and the construction of an adjoining tunnel that can reduce the overall problems is respected. In addition, it is necessary to apply the reinforcement construction method for the pillar part of the adjacent tunnel that can secure stability, economy and workability of the site. In this study, the tunnel pillar reinforcement method using prestress and grouting was reviewed. There are various reinforcement methods that can compensate for the problems of the side tunnel, but as the tunnel pillar construction method using prestress and grouting is judged to be excellent in field applicability, stability and economic feasibility, theoretical and numerical analysis of the actual behavior mechanism are conducted. Numerical analysis is divided into PC stranded wire + steel pipe reinforcement grouting + prestress (Case 1), pillar part tie bolt reinforcement (Case 2), pillar part non-reinforcement (Case 3) under the same ground conditions, and the maximum value of the celling displacement, internal displacement, and member force, the stability was confirmed. Through numerical analysis, it was confirmed that Case 1 which reinforced the PC stranded wire, was the best construction method and if it is verified and supplemented through field experiments later, it will be possible to derive superior results in terms of displacement control and member force than the currently applied reinforcement method was judged.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.5
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• pp.99-106
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• 2007

To satisfy with the increased requirements of cost reduction, labor saving, and rapid construction, the purpose of this study is to investigate the structural behavior of PSC monolithic and spliced girders. Three tests were conducted on small-scale girder specimens. This paper presents the result of experimental studies in terms of the load-deflection behavior. Different joint type and tendon amount were investigated as major variables. The monolithic girder was arranged with three tendons. The spliced girder consisted of five segments connected by three tendons. In addition, five-segmented girders connected by more than three tendons were built to examine the effect of the tendon amount. The experimental results show the difference of behavior between monolithic and spliced girders. Moreover, nonlinear finite element method analysis was utilized to verify the experimental result.

• Communications of Mathematical Education
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• v.18 no.3 s.20
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• pp.1-21
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• 2004

중국의 수학교육에서는 두 가지 기본, 즉 기본지식과 기본기술을 주창하는 전통이 있다. 이러한 전통의 직접적인 결과는, 중국 학생들이 국제수학시험(예를 들어 1989년도의 IAEP)에서 뛰어난 성적을 거둘 수 있는 능력을 갖추거나 국제수학올림피아드(IMO)에서 빼어난 성적을 거두는 것으로 나타난다. 우리는 이 강연에서, 중국 교사들이 "두 가지 기본"을 왜 그리고 어떻게 가르치는가와, 그들의 "두 가지 기본"을 학생의 창의성과 어떻게 결합시키는가를 보일 것이다. 개방형 문제해결 기법은 그러한 목적을 달성하기위한 한 가지 방법이다. 이 강연에서 생각할 주제들은 다음과 같다. 문화적 배경; 계산속도; "연습이 완전함을 만든다"라는 가설; 교실에서의 효율성; "두 가지 기본"과 개인적 성장 사이의 균형. 특히, 중국의 수학 교육자는 개방형 문제해결 기법과 "두 가지 기본" 초석 사이의 연결성에 더 많은 주의를 기울이고 있다.