• Wind and Structures
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• 제36권6호
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• pp.423-434
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• 2023

Aerodynamic force coefficients are generally obtained from traditional wind tunnel tests or computational fluid dynamics (CFD). Unfortunately, the techniques mentioned above can sometimes be cumbersome because of the cost involved, such as the computational cost and the use of heavy equipment, to name only two examples. This study proposed to build a deep neural network model to predict the aerodynamic force coefficients based on data collected from CFD simulations to overcome these drawbacks. Therefore, a series of CFD simulations were conducted using different geometric parameters to obtain the aerodynamic force coefficients, validated with wind tunnel tests. The results obtained from CFD simulations were used to create a dataset to train a multilayer perceptron artificial neural network (ANN) model. The models were obtained using three optimization algorithms: scaled conjugate gradient (SCG), Bayesian regularization (BR), and Levenberg-Marquardt algorithms (LM). Furthermore, the performance of each neural network was verified using two performance metrics, including the mean square error and the R-squared coefficient of determination. Finally, the ANN model proved to be highly accurate in predicting the force coefficients of similar bridge sections, thus circumventing the computational burden associated with CFD simulation and the cost of traditional wind tunnel tests.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 지반공학 공동 학술발표회
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• pp.601-612
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• 2005

In mountainous area, Two parallel tunnels have been usually recognized as a road tunnel which has benefits in aspects of cost and stability. However, Design and construction of 2-Arch road tunnel are growing recently due to environmental destruction, compensation of land and difficulty of route separation. As studies are mainly undergoing on only guaranteeing stability and developing a waterproofing-drainage system to avoid water leakage through comprehension for characteristics of 2-arch tunnel behaviors, there is a tendency to evaluate quantity of support by empirical method with a tunnel which has a complicated cross-section and lack of construction ability. In this study, therefore, we made a plan of tunnel cross-section which had shown good construction ability and developed the waterproofing-drainage system which is able to solve the water leakage problem fundamentally by analyzing precedented 2-arch tunnels and investigating their sites in and out of nation. We also determined fixed quantity of support by a large-scale model test and numerical analysis. We want to contribute to 2-arch tunnel design hereafter introducing design procedure and method applied here.

• 화약ㆍ발파
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• 제23권1호
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• pp.41-46
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• 2005

터널 굴착 작업에서 여굴의 발생은 필연적이라고 할 수 있다. 여굴의 발생은 터널공사에서 공사비 및 안전성에 지대한 영향을 미치게 된다. 여굴은 지질구조를 정확하게 예측하지 못하거나, 적정 장약량을 산정하지 못하는 등 다양한 원인으로 발생한다. 따라서 본 논문에서는 터널 굴착 시 여굴을 최소화할 수 있는 방안으로 다단 천공공법에 대하여 소개하고자 한다. 다단천공 공법은 기존 천공방법보다 천공비용의 증가를 초래하나, 굴착 시 여굴량을 감소시킴으로써 전체 공사비용은 감소시킬 수 있을 것으로 기대된다.

• 건설안전기술
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• 통권54호
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• pp.41-55
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• 2011

The current railway projects under plan, design, or construction have been designed as 'very long and deep underground tunnel'. Therefore, it is reasonable that the standards for preventing disaster in such conditions should be intensified in order to avoid repeating the same failure which happened in Daegu subway disaster, Although we consent to the opinion that nothing can compete with human being's life, it is very difficult to protect the life from all of potential disasters perfectly in railway fields because the excessive standards can result in excess construction cost, which can bring about cancelation of the project itself eventually. Therefore optimized disaster design standard is required to negotiate the conflict between economical cost and social tolerance limitation simultaneously.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1924-1929
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• 2010

In long tunnel If we reduce the length of system height on catenary system, tunnel construction cost is cut down. It is because of tunnel section curtailment. So that we have review reduction of system height according to tunnel section. We have designed reduction of system height considered characteristics of overhead contact systems within UIC 799 code.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2004년도 춘계학술발표회
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• pp.930-937
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• 2004

In tunnel blasting, rock damage and overbreak at excavation limits are strongly related to stability of the tunnel and cost for rock support, and also affect to maintenance after tunnel construction. In this study, many field tests and measurements have been carried out in highway tunnels so that discordance between blast design and practical production blasting could be settled and actual methods of over break control could be proposed through the understanding of the problems in existing blasting patterns. Test blasting in tunnel was carried out many times in two tunnel sites. Also, long hole blasting longer than existing blasting pattern was executed for good grade of rock mass whose RMR value is more than 60. Using the results of test blasting, new standard blasting patterns for two lane tunnel were proposed. As a result of profile measurement after blasting, drilling is a major factor of overbreak. And then the methods for minimizing overbreak were adapted in new blasting patterns.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 봄 학술발표회 논문집
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• pp.63-70
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• 2002

In tunnel construction, the information on the rock quality and the location of fault or fracture are crucial for economical design of support pattern and for safe construction of the tunnel. The grade of rock is commonly estimated through the observation with the naked eye of recovered cores in drilling or from physical parameters obtained by their laboratory test. Since drilling cost is quite expensive and terrains of planned sites for tunnel construction are rough in many cases, however, only limited information could be provided by core drilling Electrical resistivity and EM surveys may be a clue to get over this difficulty. Thus we have investigated electrical resistivity and EM field data providing regional Information of the rock Quality and delineating fault and fracture over a rough terrain. In this paper, we present some case histories using electrical resistivity and EM survey for the site investigation of tunnel construction. Through electrical resistivity and EM survey, the range and depth of coal seam was clearly estimated, cavities were detected in limestone area, and weak zones such as joint, fault and fracture have been delineated.

• 화약ㆍ발파
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• 제32권3호
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• pp.26-36
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• 2014

국내 터널공사에 사용되고 있는 뇌관의 안전성 및 경제성에 대한 의견을 알아보기 위하여 분야별 총 345명을 대상으로 설문조사를 실시하였다. 그 결과, 비전기뇌관의 안전성이 86.7%로 매우 높게 평가되었으며, 터널 굴착비 대비 뇌관이 차지하는 재료비가 8.1%임을 고려할 때 경제성보다 안전성을 우위를 둔 비전기뇌관 사용을 적극 활용한다면 터널현장의 발파사고 예방에 크게 기여할 것으로 보인다. 더불어 터널공사 국가발주처 경찰청 화약류 제조사들에게 의견수렴, 기초자료를 제공하는데 도움을 주고자 한다.

• 화약ㆍ발파
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• 제24권1호
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• pp.39-48
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• 2006

최근 들어 터널이 장대화 되면서 시공시 공기와 공사비를 감축할 수 있는 방안이 다양하게 강구되고 있다. 그러나 장대터널의 특성상 터널굴착작업이 종료된 후 콘크리트 라이닝 타설작업이 시작될 경우 공사기간 이 상당히 지연될 수밖에 없다 이에 따라 계룡터널에서는 도로터널에서 반드시 설치되는 콘크리트 라이닝 공 정과 관련하여 소요되는 공기를 단축시키기 위해 터널굴착 발파와 병행하여 라이닝을 시공하는 연구를 수행하였다. 실험은 터널막장 후방에 일정한 거리별로 모두 4 곳의 모형라이닝을 설치하고 발파계측 및 콘크리트 물성 실험을 실시하여 반복적인 발파진동하에서 콘크리트 라이닝에 영향을 미치지 않는 안전이격거리를 도출하였다. 또한 병행시공 현장적용시 환기 및 설비 재배치를 통해 작업환경을 개선하여 시공성을 확보할 수 있는 방안을 간략히 소개하고자 한다.

• Geomechanics and Engineering
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• 제13권4호
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• pp.671-683
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• 2017

Groundwater control is a significant issue in most underground construction. An estimate of the inflow rate is required to size the pumping system, and treatment plant facilities for construction planning and cost assessment. An estimate of the excavation-induced drawdown of the initial groundwater level is required to evaluate potential environmental impacts. Analytical and empirical methods used in current engineering practice do not adequately account for the effect of the jointed-rock-mass anisotropy and heterogeneity. The impact of geostructural anisotropy of fractured rocks on tunnel inflows is addressed and the limitations of analytical solutions assuming isotropic hydraulic conductivity are discussed. In this paper the unexcavated Zagros tunnel route has been classified from groundwater flow point of view based on the combination of observed water inflow and numerical modeling results. Results show that, in this hard rock tunnel, flow usually concentrates in some areas, and much of the tunnel is dry. So the remaining unexcavated Zagros tunnel route has been categorized into three categories including high Risk, moderately risk and low risk. Results show that around 60 m of tunnel (3%) length can conduit the large amount of water into tunnel and categorized into high risk zone and about 45% of tunnel route has moderately risk. The reason is that, in this tunnel, most of the water flows in rock fractures and fractures typically occur in a clustered pattern rather than in a regular or random pattern.