• 한국터널공학회:학술대회논문집
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• 2005.04a
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• pp.282-291
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• 2005

사암 및 이암을 기반암으로 하는 산악지역에 건설되는 2-아치 (2-arch) 터널의 거동을 터널설계 단계에서 분석하기 위하여 대규모 실내 모형실험을 실시하였다. 터널이 시공될 예정인 지반과 유사한 지질공학적 특성을 가지는 콘크리트 블록을 이용하여 모형지반을 조성하였다. 모형실험은 중앙터널 (pilot tunnel) 굴착을 포함한 여러 단계의 굴착과정으로 구분하여 실시되었다. 또한 터널 .공용기간 중 터널의 거동을 연구하기 위하여 터널굴착 완료 후 상재하중을 작용시켰다. 실험결과에 의하면 대부분의 지반변위는 중앙터널 굴착에 의해 발생했으며, 그 이후 터널 굴착단계에서의 변위발생은 미미한 것으로 나타났다. 또한 대부분의 지중변위는 0.25D 이내의 범위에서 발생하였다. 여기서 D 는 터널의 폭이다. 한편 실험결과를 분석하여 경암에 시공되는 2-아치 터널의 중앙벽체(centre pillar)에 작용하는 하중에 대한 경험적인 공식을 제시하였다. 터널시공 완료 후 공용기간 중 상재하중이 작용할 경우 그 크기에 따라서는 터널굴착에 의해 발생한 것보다 더 큰 지중변위가 발생할 수 있는 것으로 분석되었다. 터널의 거동은 중앙벽체의 강성에 큰 영향을 받는 것으로 나타나 이를 터널설계에 반영하여 중앙벽체의 강성을 증가시켰다. 현재 터널시공을 위한 사전작업이 진행 중에 있으며, 터널의 굴착은 2005년 하반기에 실시될 예정이다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.9 no.1
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• pp.91-97
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• 2007

Loads on the pillar and ground deformation in 2-arch tunnel, which is excavated in the rock mass with regular discontinuities, depending on the dips of discontinuities and the construction sequences were experimentally studied. Large scale model tests in the biaxial test facility were performed. Tested model (width 3.3m, height 3.0m, and length 0.45m) for 2-arch tunnel in 1/10 scale were built with various dips. Test results show that discontinuities have greate affects on the behavior of the 2-arch tunnel, especially on the pillar loads and ground deformation.

• Journal of the Korean GEO-environmental Society
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• v.5 no.4
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• pp.81-91
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• 2004

In present study, the effect of tunnel excavation on groundwater was investigated by a case study and numerical analysis. The case study revealed that groundwater can be one of environmental impacts resulting from tunnel excavation. To examine variations in groundwater level due to tunnel excavation, numerical analysis was performed. The analysis result indicated that tunnel excavation could affect the groundwater behavior as the groundwater adjacent to tunnel flows in it. Also, it was found that, for the case where groundwater flowing though fractured zone passes tunnel exacvation area, a special care with the excavation would be needed to avoid any tunnel instability due to a large qunatity of goundwater flowing in it.

• Journal of Korean Tunnelling and Underground Space Association
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• v.6 no.2
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• pp.171-182
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• 2004

This study is focused on finding out the mechanical behavior of pillars and the ground adjacent to the tunnel depending on the central tunnel size and the invert during the construction of 2 arch tunnels in the sandy ground. Model tests were performed in the trap door system, which was composed of 3 separately movable plates. Central pillar was installed on the central movable plate to measure the pillar loads during the excavation of pilot tunnel and the main tunnel. The load-transfer and the loosening load were measured at the bottom plates adjacent to the 2 arch tunnels. The ground settlement and displacement of the tunnel lining were also measured. As results, not only pillar load but also the load transfer mechanism was influenced by the construction sequences, central tunnel size, and the invert.

• Journal of the Korean Society for Railway
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• v.12 no.2
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• pp.321-328
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• 2009

A optimal reinforcement in the joint rock slope excavation adjacent to an existing tunnel would be influenced by excavation distance from the tunnel, slope angel, and joint conditions but has been empirically determined so far. In this study, large scale model tests were conducted to find out the relationship between load translation on the excavation surface and bebavior of the tunnel according to excavation steps of the jointed rock slope. Consequently, two main parameters, joint dip and sloped angle were investigated in those model tests. From the test results, it was found that tunnel deformation was the largest one when the excavation of joints located closer to the tunnel crown or invert. Stability of the slope and the tunnel were varied in a certain excavation stage related to the angle of slope. In the future, based on results of this study the reinforcement method for the tunnel and slope safety in a jointed rock mass will be demonstrated.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2006.04a
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• pp.259-262
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• 2006

본 연구는 지하처분연구시설(URT : Underground Research Tunnel)시설 건설공사와 관련하여 굴착 후의 지하수유동체계 변화를 예측하기 위하여 수행되었다. 지하수유동체계 모사를 위해 사용된 모델은 연속체 매질 개념의 Visual Modflow이며, URT 주변의 시추공에서 조사된 자료를 초기 입력자료로 이용하였다. 1단계 터널굴착 후에 계측된 지하수위 및 터널 내 지하수 유입량을 토대로 모델교정을 수행하였고, 교정된 모델을 이용하여 2단계 터널굴착 후의 지하수유동체계를 예측하였다. 1단계 굴착 후 약 4.3m의 수위강하가 발생한 KP-2번공은 2단계 굴착 후에는 약 0.05m의 수위강하가 예측되었다. 또한 2단계 굴착 후의 지하수위는 터널 입구를 기준으로 약 108m지점부터 터널 종점부 175m까지는 터널 상부에 분포하며, 종점부 175m지점에서는 지하수위가 터널 천장(roof)부로부터 약 12.7m 상부에 위치하는 것으로 예측되었다. 지하수위의 강하범위는 터널 중심부로부터 반경 약 300m까지 발생되는 것으로 예측되었고, 예상 지하수 유입량은 24.7ton/day로 1단계 공사 후보다. 약 2.7ton/day 증가하며, 공동굴착 전 터널 중심부의 지하수가 지표까지 도달하는 시간은 약 39.8년이 소요되는 것으로 나타났다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.3
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• pp.640-655
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• 2018

Recently, the construction of the urban area has been rapidly increasing, and the excavation work of the ground has been frequently performed at the upper part of the existing underground structures. Especially, when the structure is constructed after the excavation of the ground, the loading and unloading process in the ground under the excavation basement can affect the existing underground structures. Therefore, in order to maintain the stability of the existing underground structure due to the excavation of the ground, it is necessary to accurately grasp the influence of the excavation and the structure load in the adjoining part. In this study, the effect of the excavation of the ground and the new structure load on the existing tunnel was experimentally implemented and the influence of the adjacent construction on the existing tunnel was investigated. For this purpose a large testing model with 1/5 scale of the actual size was manufactured. The influence of ground excavation, width of the load due to new structure, and distance between centers of tunnel and of excavation on the existing tunnel was investigated. In this study, it was confirmed that the influence on the existing tunnel gets larger, as the excavation depth get deeper. At the same distance, it was confirmed that the tunnel displacement increased up to three times according to the increase of the building load width. That is, the load width influences the existing tunnel larger than the excavation depth. As the impact of the distance between centers of tunnel and of excavation, it was confirmed that tunnel crown displacement decreased by 48%. The result showed that a tunnel is located in the range of 1D (D: tunnel diameter) from the center of excavation, the effect of excavation is the largest.

• Journal of Korean Tunnelling and Underground Space Association
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• v.4 no.2
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• pp.167-174
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• 2002

In this study, a numerical stability analysis was performed for a large tunnel considering excavation sequence. In most cases, stability of a tunnel is analyzed based on the stability of the final excavation stage only. In this study, stability analysis of a tunnel was performed at each excavation stage. In summary, it can be inferred that there is no problem in stability of the tunnel. However, thorough and careful measurements are recommended. Also, it is found that the stability of the tunnel at the 5th excavation stage when the right half of the main tunnel is excavated is rather lower than that of the tunnel at the final excavation stage.

• Journal of the Korean GEO-environmental Society
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• v.22 no.11
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• pp.39-47
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• 2021

Tunneling is widely increased in rail-road construction due to the large portion of mountainous regions in Korea as well as the improving running performance of train. Tunneling under poor rock condition, shallow overburden, or existing fault zone has high risk for collapse. Therefore, this study presents the stability of tunnel under unfavorable geological conditions using finite element methods.

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2001.03a
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• pp.132-138
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• 2001

홍콩 HMRT(Hongkong Mass Railway Tunnel) 지하철 공사현장에서는 터널굴착시 나타난 고경사절리로 인해 상당한 여굴이 발생하였다. 이에 대한 원인을 규명하기 위하여 각 터널별로 발생한 여굴의 양과 위치 등을 조사하고 이를 입찰설계단계에서 이루어진 시추공조사와 굴착단계에서의 막장검측에 의한 지질조건과 서로 비교, 분석하였다. 터널굴착에서 발생하는 여굴은 막장의 고경사 절리의 분포와 방향에 의해 영향을 받았으며, 암반조건 RQD, Q'와도 밀접한 관계를 가지는 것으로 나타났다. 본 현장의 분석에 따르면 터널설계시 고경사절리의 존재여부 및 분포, 방향성 등을 면밀히 조사하고 해석하여 사전에 여굴의 발생 가능성을 확인하는 것이 필요하다.