• Wind and Structures
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• 제39권3호
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• pp.191-205
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• 2024

To investigate the wind load characteristics of a large-span spherical shell structure, a rigid model pressure test was conducted in a wind tunnel laboratory. The study aimed to examine the impact of various external structures and internal stacking forms on the wind loads of a spherical shell structure in a practical engineering project. This project features two adjacent spherical structures, each spanning 130 m and standing 67 m tall. These two structures are connected by trestles and a transfer station. Variations in the shape factor and the integral force coefficient of the structure were compared and analyzed under different test cases. The results indicate that when two structures are arranged in series, with the adjacent structure positioned upstream, the shape factor of the structure is most affected, resulting in a significant reduction effect at the bottom of the windward surface. Compared to the external structure, the impact of various internal stacking forms on the shape factor of the structure is relatively weak. The adjacent structure significantly improves the wind resistance of the main structure. The integral force coefficient of the structure reaches its peak when internal stacking is full and is at its lowest when there is no internal stacking.

• Geomechanics and Engineering
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• 제35권1호
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• pp.29-39
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• 2023

As the intensity of urban underground space development increases, more and more tunnels are planned and constructed, and sometimes it is inevitable to encounter situations where tunnels have to underpass the river embankments. Most previous studies involved tunnels passing river embankments perpendicularly or with large intersection angle. In this study, a project case where two EPB shield tunnels with 8.82 m diameter run parallelly underneath a river embankment was reported. The parallel length is 380 m and tunnel were mainly buried in the moderate / slightly weathered clastic rock layer. The field monitoring result was presented and discussed. Three-dimensional back-analysis were then carried out to gain a better understanding the interaction mechanisms between shield tunnel and embankment and further to predict the ultimate settlement of embankment due to twin-tunnel excavation. Parametrical studies considering effect of tunnel face pressure, tail grouting pressure and volume loss were also conducted. The measured embankment settlement after the single tunnel excavation was 4.53 mm ~ 7.43 mm. Neither new crack on the pavement or cavity under the roadbed was observed. It is found that the more degree of weathering of the rock around the tunnel, the greater the embankment settlement and wider the settlement trough. Besides, the latter tunnel excavation might cause larger deformation than the former tunnel excavation if the mobilized plastic zone overlapped. With given geometry and stratigraphic condition in this study, the safety or serviceability of the river embankment would hardly be affected since the ultimate settlement of the embankment after the twin-tunnel excavation is within the allowable limit. Reasonable tunnel face pressure and tail grouting pressure can to some extent suppress the settlement of the embankment. The recommended tunnel face pressure and tail grouting pressure are 300 kPa and 550 kPa in this study, respectively. However, the volume loss plays the crucial role in the tunnel-embankment interaction. Controlling and compensating the tunneling induced volume loss is the most effective measure for river embankment protection. Additionally, reinforcing the embankment with cement mixing pile in advance is an alternative option in case the predicted settlement exceeds allowable limit.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 춘계학술대회 논문집
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• pp.144-150
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• 2005

After the historic opening of the first section of KTX(Korea Train eXpress), it has been made changes three times in a plan to pass through cities of Daejeon, Daegu in the construction of the high speed train's second section(underground${\to}$ on ground${\to}$ under ground${\to}$ on ground). Thereafter, it has been repeatedly argued that the plan to pass through underground caused many problems such as prevention of an accident in tunnel, the difficulty of maintainence, the disadvantage of passengers' moving line. Thus construction on ground plan is coming up again with relation to the interest among local people. There have been lots of national budget loss, construction period delay in this project and people hardly trust policies about national project and nor do engineers. It will be presented that the railway line which is accorded with the characteristics of region, an agreement with local communities about national project, the reasonable procedure to determine how to pass through cities, resolve the conflict among neighborhood, and the role of engineers.

• Journal of Construction Engineering and Project Management
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• 제4권1호
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• pp.29-36
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• 2014

Tunnelling has become a preferred method of construction for road and highway projects in countries with a lot of hilly slope geological conditions such as found in Malaysia. However the construction works of a tunnelling project are usually complicated and costly, which consequently impose great risks to the parties involved. This paper identifies the key significant risks and sub-risks for tunnelling construction projects in Malaysia through a case study. Interview has been used as the solitary means to determine the significant risks from contractor's eleven key project personnel who were directly involved in the tunnelling construction such as consultant, construction manager and tunnel engineers. The importance of the risks identified is then prioritised and ranked via the Analytic Hierarchy Process (AHP)'s pairwise comparison approach to determine their criticality towards a successful delivery of project. As a result, three key risks have been identified as significant for the tunnelling case study project, namely health and safety, cost overrun in construction and time overrun in construction. Two sub-risks each of the latter categories, which are cost underestimation and unforeseen events (cost overrun in construction) as well as plant and machinery failure and delay in material delivery (time overrun in construction), have occupied the top five overall risk ranking.

• 터널과지하공간
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• 제25권1호
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• pp.37-45
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• 2015

최근 많은 도시에서 홍수와 산사태 같은 자연재해가 빈번하게 발생하고 있다. 기상이변으로 인한 집중강우로 우수유출량이 증가되어 침수피해 위험이 가중되고 있다. 부정적인 유출량 변화를 합리적으로 조절하여 도시홍수 등의 피해를 경감하려는 목적에서 우수유출 저감시설을 적극적으로 도입하려는 노력이 시도되고 있다. 따라서 이러한 시설을 적극적으로 보급하기 위하여 지하 우수저류시설 설치사업의 합리적인 분석과 대책을 마련할 수 있는 연구가 절실히 필요하게 되었다. 본 연구에서는 도시방재를 위한 부산지역 우수저류시설 설치사업의 현황과 문제점을 분석하여, 도시방재를 위한 우수저류시설 설치사업의 대책을 제안하였다.

• 터널과지하공간
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• 제23권6호
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• pp.547-560
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• 2013

최근 전 세계적으로 에너지 수급의 불안정 및 기후변화에 의한 이산화탄소 저감의 필요성으로 인하여 신재생에너지에 대한 중요성은 점차 증가하고 있다. 이러한 상황에서 지난 2010년 12월에 시작되어 진행 중인 한국 최초의 포항 인공지열 저류층 생성 기술 (Enhanced Geothermal System; EGS) 지열발전소 프로젝트는 국내 EGS 관련기술 발전에 새로운 계기가 될 것이다. 본 논문은 국내 EGS 실증사업에 일부분이라도 도움이 되고자 미국 Fenton Hill 및 일본 Hijiori 프로젝트 연구사례를 살펴보고, 이를 통해 기존 EGS 프로젝트의 성과와 한계를 습득함으로써 국내 EGS 프로젝트의 시행착오를 최소화하는데 도움이 되고자 한다.

• Structural Engineering and Mechanics
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• 제58권5호
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• pp.869-886
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• 2016

Non-Deformable Support System (NDSS) is one of the support system analysis methods. It is likely seen as numerical analysis. Obviously, numerical modeling is the key tool for this system but not unique. Although the name of the system makes you feel that there is no deformation on the support system, it is not true. The system contains some deformation but in certain tolerance determined by the numerical analyses. The important question is what is the deformation tolerance? Zero deformation in the excavation environment is not the case, actually. However, deformation occurred after supporting is important. This deformation amount will determine the performance of the applied support. NDSS is a stronghold analysis method applied in full to make this work. While doing this, NDSS uses the properties of rock mass and material, various rock mass failure criteria, various material models, different excavation geometries, like other methods. The thing that differ NDSS method from the others is that NDSS makes analysis using the time dependent deformation properties of rock mass and engineering judgement. During the evaluation process, NDSS gives the permission of questioning the field observations, measurements and timedependent support performance. These transactions are carried out with 3-dimensional numeric modeling analysis. The goal of NDSS is to design a support system which does not allow greater deformation of the support system than that calculated by numerical modeling. In this paper, NDSS applied to the problems of Tunnel 34 of the same Project (excavated with NATM method, has a length of 2218 meters), which is driven in graphite schist, was illustrated. Results of the system analysis and insitu measurements successfully coincide with each other.

• 조명전기설비학회논문지
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• 제23권9호
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• pp.6-16
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• 2009

최근 거리상의 이점에 의해 도심 터널에 보행로의 추가 설치가 늘어남에 따라 터널 내 환경이 문제가 되고 있다. 그러므로 본 연구는 도심 터널 보행로의 조도 및 불쾌글레어를 측정하여 실제 보행자가 느끼는 빛 환경에 대한 실태조사를 실시하였다. 조도와 불쾌글레어의 물리적인 측정은 동작구에 위치한 'S터널'을 대상으로 야간과 주간으로 구분하여 실시되었다. 또한 실제 보행자가 느끼는 주관적 반응을 알아보기 위해 밝기와 불쾌 글레어에 대한 설문조사를 실시하였다. 조사 결과, 보행자는 야간보다 주간에 보행로를 어둡게 느끼는 것으로 나타났으며, 불쾌글레어 지수는 야간의 경우 더 높게 나타남을 알 수 있었다. 본 연구의 결과는 서울시에서 실시하고 있는 '터널보행로 환경개선 사업'에 있어 조명환경 개선을 위한 기초자료로 사용될 수 있을 것이라 생각된다.

• 조명전기설비학회논문지
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• 제18권4호
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• pp.1-7
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• 2004

우리나라의 지형은 많은 산들로 이루어져 있으며 최근에는 교통량의 증가와 물류비용의 절감 등의 목적으로 많은 터널이 건설되고 있다. 터널에서의 조명은 안전한 도로조건을 만들기 위한 가장 중요한 설비이다. 과거에는 조명기구를 벽면에 설치하였으나 최근에는 천장에 설치하고 있으며 조명기구를 천장에 설치하더라도 어느 위치에 설치하여야 적절한지를 알 수가 없어 설계자의 임의로 설계를 하고 있는 실정이다. 이런 문제를 해결하고자 풍부한 경험과 정확한 데이터를 가지고, Lightscape program을 사용하여 계산 및 시뮬레이션을 시행하여 적정한 위치를 연구 검토하였다. 검토결과 조명기구를 벽면에 설치하는 것보다 천장에 설치하는 것이 균제도가 균일하고 조명률이 높아 경제적이며 휘도비도 대체로 좋다. 그러므로 터널에서는 조명기구의 위치를 일반적으로 벽면보다 천장에 설치하는 것이 바람직하겠다.

• 한국터널지하공간학회 논문집
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• 제5권2호
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• pp.115-134
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• 2003

최근 도로설계시 두 개의 터널이 짧은 거리로 계속적으로 존재하는 연속터널에 대한 설계사례가 증가하고 있다. 이러한 경우에 있어, 한 터널내에서 발생한 오염물질은 다른 터널로 재유입하여 터널환기 시스템에 중대한 영향을 미치게 되므로, 이에 대한 적절한 환기검토가 수행되어야 한다. 본 연구에서는 동해 고속도로 설계시 나타난 연속터널을 대상으로 하여 1차원 터널내 오염농도 해석 및 3차원 CFD 해석 프로그램을 사용하여 터널내 오염농도의 거동 및 터널 갱구부 주변의 오염물질의 재유입 여부를 분석하여, 연속터널에 대한 터널내 외부유동에 대한 환기영향을 검증하였다. 이를 위하여 해당지역인 속초지방의 기상데이터를 분석하고, 기상조건에 따른 터널내부의 공기환경을 검토하였으며, 3차원 시뮬레이션을 통하여 각각의 터널에 대한 재유입 여부 및 재유입율을 분석하였다.