• Title/Summary/Keyword: excavation method

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A Study on the Conservation of Lady Shim's Costume Excavated in Jecheon Province (제천출토 청송심씨 출토유물의 보존처리)

  • Park, Bong Soon;Lee, Mok Kun;Chang, In Woo
    • Journal of the Korean Society of Costume
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    • v.65 no.7
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    • pp.47-59
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    • 2015
  • This paper studies the conservation treatment of Lady Shim's costume, which was excavated in Jecheon Province in 2012. There were the significant problems, which were encountered in the treatment of the costume ; First the Jeogoris were transformed during the excavation, Second fibers were seriously deteriorated, Third most of the fabrics such as Chusa were readily deformed. To overcome these problems and to secure stability in the conservation treatment, we decided to alternate between two different washing methods ; dry cleaning by n-hexane and wet cleaning by water. The costume shape was recovered by steaming and by swelling with Hanji(Korean traditional paper). The combined cleaning method proved to be relatively efficient and stable. In addition, the shape of Chusa was well preserved by dry cleaning.(using n-hexane also solved the problem of bad smell after washing with organic solvents.) The effects of the conservation treatment on the excavated costumes could be seen in the change of Lab color difference. Washing made the distribution of Lab color difference narrower, which may suggest that the impurities on the fiber was removed by washing. In addition, the value of L was greater than a-value and b-value after the treatment. This result indicates that the change of value represents the change of color difference by cleaning.

Numerical estimation for safety factors of tunnels considering the failure of supports (지보재 파괴를 고려한 터널 안전율의 수치해석적 산정 연구)

  • You, Kwang-Ho;Park, Yeon-Jun;Hong, Keun-Young;Lee, Hyun-Koo;Kim, Jea-Kwon
    • 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.

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Analysis and the Conservation Treatment of the Paper Relics of the Seonwon Temple Area (선원사지(禪源寺地)출토 지류 유물의 분석 및 보존 처리 방법)

  • Lim, Ju-Hee;Park, Chi-sun
    • Journal of Conservation Science
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    • v.12 no.1 s.15
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    • pp.71-82
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    • 2003
  • The paper relics excavated from the 4th excavation of the historical spot No.259 Seonwon temple area were analyzed and conserved. Because these works remained folded, the most important conservation treatment was a separation. This process depended on the state of the works: dry state works were separated using Gore-Tex chamber and the filtrated water, wet state works were separated through vacuum freeze drying method. Analyses of the paper relics performed were examination on the paper to find its distinction, binocular microscope and SEM on fiber, and XRF on character ingredient. This study presumed the times though $C^{14}$ dating of these works. The works were able to be classified through analysis and conservation treatment. This separation made lost part of the works conserve an archetype. This study presented the application of conservation methods on the paper relics which are in the bad condition and obtained information through carbon dating of it.

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A Study on Analysis for the Characteristics of Fault Zone at Mica-schist for Reinforcement of Large-Span Tunnel (대단면 터널 보강을 위한 운모편암 단층대 특성 분석에 관한 연구)

  • Chung, Hoi-Yong;Kim, Young-Geun;Park, Yeon-Jun;You, Kwang-Ho
    • Tunnel and Underground Space
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    • v.19 no.2
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    • pp.132-145
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    • 2009
  • Faults in rock mass have strong influences on the behaviors of rock structure such as rock slope, tunnel and underground space. Thus, it is very important to analyse for the characteristics of fault rocks in design for tunnel. But, due to the limitation of geotechnical investigation in design stages, tunnel engineers have to carry out the face mapping and additional geological survey during tunnel excavation to find the distribution of faults and the engineering properties of faults for support and reinforcement design of tunnel. In this study, various geological survey and field tests were carried out to analyse the characteristics of the large thrust fault zone through the large sectional tunnel is constructed in mica-schist region. Also, the distribution of structural geology, the shape of thrust faults and the mechanical properties of fault rock were studied for the reasonable design of the reinforcement and support method for the highly fractured fault zone in the large-span tunnel.

A Case Study on the Construction of Large Cross Section Tunnel for Underground Ventilation System (지하환기소 대단면 터널 시공 사례 연구)

  • Noh, Seung Hwan;Choi, Sung Wook;Noh, Sang Lim
    • Tunnel and Underground Space
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    • v.27 no.4
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    • pp.195-204
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    • 2017
  • This case study introduces the construction of large cross section tunnel for underground ventilation system in Sillim-Bongcheon Tunnel Project. In order to grant the safety and efficiency in connecting the ventilation shaft (7.8 m of width, and 6.6 m of height) to a tunnel for axial fan facility (20.8 m of width, and 12.3 m of height), gradual enlargement of tunnel cross section was employed between those and temporary support method was determined based on Q system. In addition, some original designs were revised during construction stage to improve the efficiency of excavation in large cross section tunnel. The advance length was optimized and top heading of the tunnel was excavated without partition in accordance with ground condition and numerical stability analysis results. It is believed that some experiences and considerations in this case study will be useful for the future design and construction in similar large cross section tunnel such as large underground ventilation system or road tunnel with four lanes.

Review of Applicability of the Standard Blasting Patterns of MLTM to Various Rock Types (국토해양부 표준발파패턴의 셰일암반 적용성에 관한 사례 연구)

  • Kim, Se-Hyun
    • Explosives and Blasting
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    • v.27 no.1
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    • pp.47-52
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    • 2009
  • Blasting is necessary for excavation processes since more than 70% of korean land is consist of mountains. The vibration and noise accompanied by blasting processes usually bring about public complaints. Blasting patterns are chosen by economical efficiency, stability and construction conveniency. However, there are many alternatives without control to settle the popular complaint. To prevent those alternatives, standard blasting method for design and construction were suggested by MLTM (Ministry of Land, Transport and Maritime Affairs) in 2006. However, standard blasting pattern of MLTM was designed in a lump irrespective of types of rocks. Economical loss may occur by ignoring the characteristics of rocks for the applications to the rocks with low intensity, such as shale, or containing many joint. We deduced some economical progresses by performing test blasting with adjusted drilling spacing and length of burden considering the characteristics of local rock. This paper suggests the start of case studies for different applications. Economic improvement can be expected by applying those results deduced from case studies to design and construction.

A natural analog study on the cover-layer performance for near-surface LILW disposal by considering the tomb of historical age (역사시대 고분을 이용한 중저준위 방사성폐기물의 천층처분 덮개성능 자연유사연구)

  • Park Jin-Beak;Park Joo Wan;Kim Chang-Lak;Yang Si Eun;Lee Sun Bok
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.3 no.4
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    • pp.279-291
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    • 2005
  • To support the design concept and the performance assessment of the cover system for low- and intermediate-level radioactive waste(LILW) disposal facility, a pioneering study is conducted for the tomb of historical age. Research status of the art are investigated and the characteristics of tomb cover are summarized based on the preservation status of historical remains. On-site soil samples are prepared and their unsaturated hydraulic conductivities are measured by an one-step outflow method. Visiting the excavation site of historical tomb and communication with Korean archeological society are required for the further understanding and for the extension to the radioactive waste disposal research.

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A Preliminary Study on the Reused Channel-Type Lining Board with Corrosion-Damage (부식 강재 복공판의 재사용성 평가에 관한 기초적 연구)

  • Kim, In-Tae;Kim, Dong-Woo;Choi, Hyoung-Suk;Cheung, Jin-Hwan
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.13 no.4 s.56
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    • pp.170-179
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    • 2009
  • Channel-type lining board(CLB) is a welded steel structure used in the field of open cut subway excavation and building basement construction. Lining board is generally installed at the underground environment which is exposed to corrosion factors such as humidity, temperature and corrosive gases. This study evaluates reusability of the corroded lining board by experimental and analytical method. Static loading tests were performed to know serviceability of corroded CLB after checking thickness loss of the used CLB parts. Strain of the plates and middle point deflection was measured simultaneously. According to experimental test results and comparison with numerical analysis, the thickness loss of the plates by corrosion makes more vertical displacements and stresses in members under the DB vehicle load considering impact factor. As a result, this paper is proposed a way to evaluate used and corroded CLB by checking the plates thickness and it makes construction engineers easy to know optimal time to replace their old CLBs with new one.

The Case Studies on Application of Mat Foundation System to Building Structure Founded on Weathered Ground (풍화대지반에 지지된 건축구조물의 전면기초 적용에 관한 사례 연구)

  • Choi, Yongkyu;Kim, Sungho;Lee, Minhee
    • Journal of the Korean GEO-environmental Society
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    • v.10 no.6
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    • pp.5-18
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    • 2009
  • In construction of buildings in Korea, the buildings are frequently founded on the weathered ground (weathered soil/rock, fractured rock). In this case, to make a full use of a bearing capacity of a weathered ground for economic design, the shallow mat foundation system could be used. In this study, we have researched three cases of mat foundations on the weathered ground in Korea, and analyzed and considered the design procedures and the reinforcing methods. That is, we have considered the detail design, analysis proceedings, the ground settlement evaluation proceedings, the rock face mapping evaluations after excavation and reinforcing methods of the mat foundation on the weathered ground. And large scale plate load tests on the weathered ground supporting the mat foundation were performed and also load bearing capacity and settlement of actual mat foundation, considering the scale effect, were evaluated.

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Development of Optimal Design Simulation Model for Least Cost Urban Sewer System Considering Risk (I) (위험도를 고려한 최소비용 도시우수관망 설계의 최적화 모형개발 (I): 모형의 개발과 시험유역의 적용)

  • Jang, Suk-Hwan;Park, Sang-Woo
    • Journal of Korea Water Resources Association
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    • v.38 no.12 s.161
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    • pp.1021-1028
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    • 2005
  • This study purpose to develop simulation model of optimal design condition of urban storm sewer system considering risk. Urban Storm Sewer Optimal Design Model(USSOD) can compute pipe capacity, pipe slope, crown elevation, excavation depth, risk and return cost in the condition of design discharge. Rational formula is adopted for design discharge and Manning's formula is used for pipe capacity. Discrete differential dynamic programming(DDDP) technique which is a kind of dynamic programming(DP) is used for optimization and first order second moment approximation method and uncertainty analysis is also for developing model. USSOD is applied to hypothetical drainage basin to test and verify, which resulted economical and efficient design in urban drainage sewer system.