• Title/Summary/Keyword: 지보

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A study on the optimization of tunnel support patterns using ANN and SVR algorithms (ANN 및 SVR 알고리즘을 활용한 최적 터널지보패턴 선정에 관한 연구)

  • Lee, Je-Kyum;Kim, YangKyun;Lee, Sean Seungwon
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.24 no.6
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    • pp.617-628
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    • 2022
  • A ground support pattern should be designed by properly integrating various support materials in accordance with the rock mass grade when constructing a tunnel, and a technical decision must be made in this process by professionals with vast construction experiences. However, designing supports at the early stage of tunnel design, such as feasibility study or basic design, may be very challenging due to the short timeline, insufficient budget, and deficiency of field data. Meanwhile, the design of the support pattern can be performed more quickly and reliably by utilizing the machine learning technique and the accumulated design data with the rapid increase in tunnel construction in South Korea. Therefore, in this study, the design data and ground exploration data of 48 road tunnels in South Korea were inspected, and data about 19 items, including eight input items (rock type, resistivity, depth, tunnel length, safety index by tunnel length, safety index by rick index, tunnel type, tunnel area) and 11 output items (rock mass grade, two items for shotcrete, three items for rock bolt, three items for steel support, two items for concrete lining), were collected to automatically determine the rock mass class and the support pattern. Three machine learning models (S1, A1, A2) were developed using two machine learning algorithms (SVR, ANN) and organized data. As a result, the A2 model, which applied different loss functions according to the output data format, showed the best performance. This study confirms the potential of support pattern design using machine learning, and it is expected that it will be able to improve the design model by continuously using the model in the actual design, compensating for its shortcomings, and improving its usability.

Scale Model Studies for Stability Estimation of Twin Tunnels with Small Clearance (근접병설터널의 안정성 평가를 위한 모형실험 연구)

  • Kim, Pyoung Gi;Kim, Jong Woo
    • Tunnel and Underground Space
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    • v.23 no.2
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    • pp.130-140
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    • 2013
  • In this study, scaled model tests were performed to investigate the stability of twin tunnels with small clearance, where the pillar widths were 0.5D and 0.25D, respectively. The tunnels were supposed to be constructed in anisotropic weathered rocks with $30^{\circ}$ inclined bedding planes, and the model tests were conducted under the condition of lateral pressure ratio, 1. Six types of test models which had respectively different pillar widths and support conditions were experimented, where crack initiating pressures, maximum pressures, failure modes of pillar and deformation behaviors around tunnels were investigated. The models with wider pillar were cracked under higher pressure than the models with shallower pillar. The models with lining support were cracked under higher pressure and showed less tunnel convergence than the unsupported models. The models with both lining and pillar reinforcement were proved to be most stable among the tested models. In particular, as the model of 0.25D pillar width with only lining support showed shear failure of pillar according to the existing bedding planes, so both lining and pillar reinforcement were thought to be indispensable in that case of tunnel.

Evaluation of the Standard Support Pattern in Large Section Tunnel by Numerical Analysis and Field Measurement (수치해석 및 현장계측에 의한 대단면 터널 표준지보패턴의 적정성 검증)

  • Byun, Yoseph;Chung, Sungrae;Song, Simyung;Chun, Byungsik;Park, Duhee
    • Journal of the Korean GEO-environmental Society
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    • v.12 no.7
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    • pp.5-12
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    • 2011
  • When choosing the support pattern of tunnel, the characteristics of rock are identified from the result of the surface geologic survey, boring, and geophysical prospecting and laboratory test. And a rock mass rating is classified and excavation method and standard support pattern are designed considering rock classification, domestic and international construction practices, numerical analysis. According to the revised design standard for tunnel, it was recommended to classify the rock mass rating for the design of tunnel into a rating based on RMR. If necessary, it proposed a flexible standard allowed applying more atomized the rock mass rating and Q-System. Also, the resonable verification of the support pattern must be accompanied because the factors affecting the structure and behavior of ground during the construction of tunnel are the main factors of uncertainty factors such as the nature of ground, ground water and the characteristics of structural materials. These days, such verification method is getting more specialized and diversified. In this study, the empirical method, numerical analysis and comparative analysis of in situ measurements were used to prove the reasonableness in the support pattern by RMR and Q-value on the Imha Dam emergency spillway.

Case Study of Deep Geological Disposal Facility Design for High-level Radioactive Waste (스웨덴 고준위방사성폐기물 심층처분시설의 설계 사례 분석)

  • Juhyi Yim;Jae Hoon Jung;Seokwon Jeon;Ki-Il Song;Young Jin Shin
    • Tunnel and Underground Space
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    • v.33 no.5
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    • pp.312-338
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    • 2023
  • The underground disposal facility for spent nuclear fuel demands a specialized design, distinct from conventional practices, to ensure long-term thermal, mechanical, and hydraulic integrity, preventing the release of radioactive isotopes from high-temperature spent nuclear fuel. SKB has established design criteria for such facilities and executed practical design implementations for Forsmark. Moreover, in response to subsurface uncertainty, SKB has proposed an empirical approach involving monitoring and adaptive design modifications, alongside stepwise development. SKB has further introduced a unique support system, categorizing ground types and behaviors and aligning them with corresponding support types to confirm safety through comparative analyses against existing systems. POSIVA has pursued a comparable approach, developing a support system for Onkalo while accounting for distinct geological characteristics compared to Forsmark. This demonstrates the potential for domestic implementation of spent nuclear fuel disposal facility designs and the establishment of a support system adapted to national attributes.

NATM시공 산악터널에서 암반분류 및 계측에 의한 지보공 선정 사례연구

  • 김영근;장정범;정한중
    • Proceedings of the Korean Society for Rock Mechanics Conference
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    • 1996.03a
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    • pp.25-34
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    • 1996
  • 터널은 긴 선상구조물로서 사전지질조사에 의해 설계에 필요한 정보를 정밀도 높게 구하는 것이 매우 어렵다. 따라서 터널시공 중 암반 및 지질상황을 관찰하고, 터널주변 지반의 거동을 계측하여 지반에 적합한 지보공을 설계ㆍ시공하는 것이 필수적이다. 이를 위해서 터널시공 중 정량적인 암반분류와 계측(일상관리계측과 대표단면계측)이 주기적으로 실시되고 있지만, 이러한 결과를 어떻게 시공에 반영하느냐는 터널의 합리적인 시공에 있어 매우 어려우면서도 중요한 문제라 할 수 있다. (중략)

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A Study on Rock Mass Rating system(RMR) and Modified Method (RMR 분류방법 및 수정 방법의 고찰)

  • 허종석
    • Proceedings of the Korean Geotechical Society Conference
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    • 2003.06b
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    • pp.51-64
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    • 2003
  • Bieniawski에 의해 개발된 RMR은 암석강도 및 불연속면, 지하수 등의 6개 인자에 따라 분류되어, 이들을 합산하여 결정된다. RMR 분류법은 각 요소들에 대한 평가가 비교적 쉽고, 다양한 응용을 거쳐 여러 분야에 적용되어 국내에서도 가장 널리 사용하고 있는 암반분류 방법 중의 하나이다. RMR 분류결과는 터널의 유지시간, 최대 무지보폭의 예측, 지보량 산정, 암반의 물리적 특성값 예측 등에 적용될 수 있다. 또한 RMR 분류법을 사면안정, 댐 기초, 심부 광산 등에 적용하거나, RMR 분류법의 미비한 부분을 보완하기 위한 여러 가지 수정방법이 제시되었다.

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블록반응곡선을 이용한 불연속 암반내 공동에 대한 지보설계에 관한 연구

  • 이영주;이희근
    • Proceedings of the Korean Society for Rock Mechanics Conference
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    • 1995.03a
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    • pp.41-47
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    • 1995
  • NATM공법에서 지보는 주로 암반반응곡선(Ground Reaction Curve, GRC)상에서 설계된다. 그러나 GRC는 유도과정에서 많은 가정을 지니고 있어 시공에 직접 반영하기에는 많은 한계를 지닌다. 특히 과지압에 의한 소성거동의 문제가 심각하지 않고, 암반의 거동이 불연속면에 영향을 많이 받는 지역에서는 GRC의 가정 중에 하나인 등방 연속체라는 가정은 큰 결점 중의 하나이다. (중략)

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암석역학 전문가 시스템(ROMES)에 의한 암반분류 연구

  • 양형식;김남수;이희근;김호영
    • Proceedings of the Korean Society for Rock Mechanics Conference
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    • 1995.03a
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    • pp.181-185
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    • 1995
  • 현재 구미에서 터널의 설계에는 RMR, Q와 같은 암반분류 기법과 경계요소 해석법과 같은 간략한 탄성 프로그램에 경험적 파괴조건식을 적용하여 이완대를 계산하고 터널의 지보량을 추정하는 방식이 널리 적용되고 있다. RMR이나 Q와 같은 암반분류법은 지하공동의 안정성에 영향을 미치는 중요한 지질 요인들에 근거하여 암반을 몇가지 등급으로 분류하고 지보방법을 결정하는 분류 방식으로 가장 많이 사용되고 있으나 각 항목의 평가방식이 경험적인 판단을 요하게 되어 주관적인 오류에 빠질 가능성이 많고, 또 여러 가지 대체 수단이 있어 종합적인 판단을 얻기가 용이하지가 않다. (중략)

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