• Title/Summary/Keyword: 철도건설공사

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Nonlinear Seismic Performance Evaluation of an Operating TBM(Tunnel Boring Machine) Tunnel (공용 중인 TBM(Tunnel Boring Machine) 터널의 비선형 내진성능 평가 )

  • Byoung-Il Choi;Dong-Ha Lee;Jin-Woo Jung;Si-Hyun Park
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.28 no.5
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    • pp.1-9
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    • 2024
  • Recently, the TBM tunnel construction method has been in the spotlight as tunnel excavation under urban areas such as the Metropolitan Rapid Transit (GTX) has been actively carried out. Although the construction cost of the TBM tunnel is high, it is relatively free from noise and vibration compared to the NATM tunnel method, so it is well known to be a suitable construction method for application to the lower part of urban areas. In particular, when the stratum passes through the shallow section, it can have a great impact on existing upper structures and obstacles, so accurate numerical analysis considering various variables is required when designing the TBM tunnel. Unlike other tunnel construction methods, TBM tunnels build linings by assembling factory-made segments. Unlike NATM tunnels, segment lining has connections between segments, so how to the connection status between segments is reflected can have a significant impact on securing the reliability of analysis results. Therefore, in this paper, a segment joint model(Janssen Model) was applied to the lining for seismic analysis of the TBM tunnel, and the tunnel's behavioral characteristics were analyzed after numerical analysis using nonlinear models according to urban railway seismic design standards.

Implementation of the Urban Development Projects in Ulaanbaatar (도시개발 여건을 고려한 울란바타르 건설사업 참여방안)

  • Jeong, Yeun-Woo;Seong, Jang-Hwan
    • Land and Housing Review
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    • v.3 no.4
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    • pp.357-367
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    • 2012
  • The efficient business scheme were suggested with the consideration of the local development condition at Ulaanbaatar. Major findings of the study were presented as follows. First, high level of education and the underground resources are presented as the merits of Mongolia. On the other side, the defects are limited domestic demands of 2.6 millions of population and the insufficiency of the infrastructure. The improvement of the infrastructures like roads, water & sewage, electric power, and heating is urgent while the development pressure of Ulaanbaatar is expected to be high due to the continuous inflow of population. Secondly, the Mongolian land system consists of the right of ownership, lease and use, therefore there are some differences among the right of land. Thirdly, definite business scheme to sell land in lots and to sell buildings in lots are suggested which are actual methods to participate in the development project in Ulaanbaatar. Moreover, enhancing the possibility to sell the lands, fixing the proper sale price to secure the profit, finding the proper buyer for the profitable lands, investing of quota and guaranteeing of granting the principal and interest by the Mongolian government, etc. are presented as consideration when participate in projects.

Evaluation of the Mechanical Properties of Field-Cast Shotcrete and Long-Term Durability by Combined Deterioration Test (현장타설 숏크리트의 역학적 성능 평가 및 복합열화시험을 통한 장기내구성 평가)

  • Ma, Sang-Joon;Jang, Phil-Sung;Kim, Dong-Min;Choi, Jae-Seok
    • Journal of the Korea Concrete Institute
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    • v.19 no.1
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    • pp.47-56
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    • 2007
  • Recently, tunnels are increasingly constructed in this country with the increased construction of highways, high-speed railways and subways. Shotcrete is one of the major processes in the tunnel construction. Many problems, however, exist in the current shotcrete practice. The purpose of the study is, therefore, to explore the trobles in the current shotcreting practice, and to develop high-quality silica fume shotcrete. For the purpose of security a long-term durability of shotcrete, this study conducted combined deterioration tests. In this study, a combined deterioration test in consideration of a variety of deterioration factors were proceeded. Especially, micro-silica fume that was used frequently in overseas because of a outstanding strength-promotion effect was applied to combined deterioration test, and a long-term durability of shotcrete was investigated according to additions mixing. As a result of test, the shotcrete mixed Micro-silica fume showed a good deterioration quality compared with the other mixes. And is shows that the Micro-silica fume has an outstanding strength-promotion effect and is effective to secure a long-term durability of shotcrete by means of decreasing a deterioration caused by steel fiber mixed.

Estimation Method of Resilience Pads Spring Stiffness for Sleeper Floating Tracks based on Track Vibration (궤도 진동기반의 침목플로팅궤도 침목방진패드 스프링강성 추정 기법 연구)

  • Jung-Youl Choi;Sang-Wook Park;Jee-Seung Chung
    • The Journal of the Convergence on Culture Technology
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    • v.9 no.6
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    • pp.1057-1063
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    • 2023
  • The urban railway sleeper floating track, the subject of this study, is an anti-vibration track to reduce vibration transmitted to the structure. currently, the replacement cycle of resilience pad for sleeper floating tracks is set and operated based on load. however, most previous studies were conducted on load-based structural safety aspects, such as fatigue life evaluation of sleeper anti-vibration pads and increase in track impact coefficient and track support stiffness due to increase in spring stiffness. therefore, in this study, we measure the vibration acceleration of the ballast for each analysis section and use the results of 7 million fatigue tests to calculate the spring stiffness of the resilience pad for each section. the spring stiffness of the resilience pad calculated for each section was set as the analysis data and the concrete vibration acceleration was derived analytically. the adequacy of analysis modeling was verified as the analyzed concrete bed vibration acceleration for each section was within the field-measured concrete bed vibration acceleration range. using the vibration acceleration curve according to the derived spring stiffness change, the spring stiffness of the resilience pad is estimated from the measured vibration acceleration. therefore, we would like to present a technique that can estimate the spring stiffness of resilience pad of a running track using the vibration acceleration of the measured concrete bed.

Development of the Purlin Hanging System Form for the Girder Bridge Slab and Economic Analysis (거더교 상판 콘크리트 타설용 거푸집 개발 및 경제성 분석)

  • Lim, Jeeyoung;Kim, Sunkuk;Son, Kiyoung
    • Journal of the Korea Institute of Building Construction
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    • v.16 no.3
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    • pp.271-278
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    • 2016
  • In the case of South Korea, steel girder bridge (steel box or H-steel) and PSC (Pre-Stressed Concrete) girder bridge are the representative upper structures of railroad and road bridges. These structures account for 75% of the total bridge constructions and 80% of the total construction cost. Since the form work for concreting bridge slab is difficult, various construction methods developed and applied. However, several problems in those methods did not solve partially, including cost increase by material loss and rise of labor costs, quality deterioration by unskilled workers, increased construction time by complicated method, reduced productivity, safety accident by high place work, difficult transportation by big member, and rise of maintenance cost by material characteristic. Alternative method is needed to solve problems of as-is methods. Therefore, the purpose of this study is development of the purlin hanging system form for the girder bridge slab and its economic analysis. Through the findings of this study, it was verified that the purlin hanging system form is possible 60% reduction in cost and 80% reduction in time as comparison with conventional method.

An analysis study for reasonable installation of tunnel fire safety facility (터널 방재설비의 합리적 설치를 위한 분석적 연구)

  • Park, Jin-Ouk;Yoo, Yong-Ho;Park, Byoung-Jik
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.17 no.3
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    • pp.243-248
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    • 2015
  • Domestic road and railroad construction have been increasingly growing and for reasons of mitigating traffic congestion, urban plan and refurbishment project, deeper and longer tunnels have been built. The event of fire is the most fatal accident in a tunnel, and it can be very disastrous with a high possibility. In this study, QRA (Quantitative Risk Analysis) which is one of quantitative risk analysis approaches was applied to tunnel fire safety design and the evaluation of QRA cases and the cost comparison of QRA methods were carried out. In addition analysis of risk reduction effect of tunnel fire safety system was conducted using AHP (Analytic Hierarchy Process) and the priority of major factors that could mitigate the risk in tunnel fire was presented. As a result, significant cost reduction effect could be obtained by incorporating QRA and it is expected to design fire safety system rationally. The priority of fire safety system based on risk mitigation effect by fire safety system considering the cost is in order of water pipe, emergency lighting, evacuation passage and smoke control system.

A Case Studty on the Ground Reinforcement and Waterproofing Effect of Weathering and Fault Zone by Special Injection Tip Equipment Using Microcement Type (특수주입선단장치에 의한 마이크로시멘트계 약액주입의 풍화대, 단층파쇄대의 지반보강 및 차수효과 사례연구)

  • Do, Jongnam;Jung, Jongju;Chun, Byungsik
    • Journal of the Korean GEO-environmental Society
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    • v.10 no.2
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    • pp.21-28
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    • 2009
  • A grouting method has been widely used in construction of large-scale structure to reduce permeability and reinforce the ground. If cement and grout material were not mixed well in the injection tip equipment, an opposite flow and interception state of the chemical grouting can occur. McG (Multi-mixing counterflow prevented Grouting, McG) method installed a special grouting device to allow better mixing of the grouting material(above fineness $6,000cm^2/g$) and prevent backward flow. The block of nozzle also diversify powder rate of cement. YSS (Youngil Special Silicate, YSS) that lowers $Na_2O$ and thereby increases durability was developed by gel-forming reaction material. The seepage state and unconfined compressive strength of the injection material using the special injection tip equipment was tested in this study. The results of this study showed that the uniaxial compressive strength, permeability, N-value, TCR and RQD were improved by this method. Engineering characteristics obtained by the special injection tip method will be compared with those by the other method through various field tests from now on.

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A Numerical Analysis Study for Estimation of Ultimate Bearing Capacity and An Analysis of the High Capacity Bi-directional Pile Load Tests of the Large-diameter Drilled Shafts (대구경 현장타설말뚝의 대용량 양방향 말뚝재하시험 분석 및 극한지지력 추정을 위한 수치해석 연구)

  • Nam, Moonsuk;Kim, Sangil;Hong, Seokwoo;Hwang, Seongchun;Choi, Yongkyu
    • Journal of the Korean GEO-environmental Society
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    • v.12 no.10
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    • pp.63-72
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    • 2011
  • The high capacity bi-directional pile load test is an optimum pile load test method for high-rised buildings. Especially, a high pressure and double-acting bi-directional pile load testing, a special type of the high capacity bi-directional pile load test, is the most practical way to overcome limitations of loading capacities and constraints of field conditions, which was judged to be a very useful test method for requiring high loading capacities. Total of 2 high capacity bi-directional pile load tests(P-1 and P-2) were conducted in high-rised building sites in Korea. Based on the field load test results, the sufficiency ratio of loading capacities to design loads for P-1 and P-2 were 3.3 and 2.1, respectively. For P-2, the load test could not verify the design load if 1-directional loads applied slightly smaller than the actual applied load. Also, high capacity bi-directional pile load tests were difficult to determine an ultimate state of ground or piles, although the loads were applied until their maximum loads. Hence, finite element analyses were conducted to determine their ultimate states by calibrating and extrapolate with test results.

A Study on the Management of the Sectional Superficies for the Realization of 3D Cadastre (입체지적 구현을 위한 구분지상권의 관리에 관한 연구)

  • Kim, HyunYoung;Lih, BongJoo
    • Journal of Cadastre & Land InformatiX
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    • v.51 no.2
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    • pp.107-123
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    • 2021
  • In recent years, due to the continuous density and urbanization of space, the expansion of awareness of rights, the need for landscape conservation, and the development of construction technology, the conventional flat land use has been deviated from the conventional flat land use, and the transmission line, urban railway, parking lot, communal district, underground shopping mall, pipeline, etc. Although 3D spatial activities are carried out in the form of 3D space, there are considerable difficulties in administration to manage the 3D use of land due to the inadequacy of related regulations. In this background, for the administration that can manage Sectional Superficies, which is a representative case of 3D spatial use of parcels, which is a registered unit of land, first, the law on the establishment and management of spatial information, and cadastral re-examination from the legal and institutional aspects Standardization of 3D space registration through amendments to the Special Act, etc. and the formation of consensus among related departments. Second, in technical and administrative aspects, the registration of Sectional Superficies based on cadastral survey results, establishment of a platform for integrated management of location and attribute data, and registration method was found to be in need of improvement. As suggested in this study, by registering and managing Sectional Superficies, it is possible to manage various 3D land use of not only ground space or surface space but also underground space. It is expected to be able to register and manage lot-based 3D land use efficiently.

Cause Analysis for Sleeper Damage of Sleeper Floating Track in Urban Transit (도시철도 침목플로팅궤도의 침목손상 원인 분석)

  • Choi, Jung-Youl;Shin, Hwang-Sung
    • The Journal of the Convergence on Culture Technology
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    • v.8 no.6
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    • pp.667-674
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    • 2022
  • In this study, the correlation between the damage type and operating conditions of the sleepers was analyzed based on the design data and visual inspection results for the concrete sleepers of the sleeper floating track (STEDEF) that have been in operation for more than 20 years. It appeared in the form of cracks, breakages, and breaks in the concrete at the center and tie bar contact and buried areas. As a result of the numerical analysis, it was analyzed that the change in the left and right spring stiffness of the sleeper resilience pad increases the maximum stress, tensile stress, compressive stress, and displacement of the concrete sleeper, and stress concentration in the concrete at the tie bar contact area. It was proved analytically that the sleeper resilience pad can affect the damage of the concrete sleeper. Therefore, damage of concrete sleepers in the sleeper floating track in urban transit could be caused by changes in spring stiffness of sleeper resilience pads. It was reviewed that preventive maintenance such as improvement and timely replacement of sleeper resilience pads was necessary.