• Geomechanics and Engineering
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• 제22권1호
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• pp.81-95
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• 2020

Measurement of the unconfined compressive strength (UCS) of the rock is critical to assess the quality of the rock mass ahead of a tunnel face. In this study, extensive field studies have been conducted along 3,885 m of the new Nagasaki tunnel in Japan. To predict UCS, a hybrid model of artificial neural network (ANN) based on genetic algorithm (GA) optimization was developed. A total of 1350 datasets, including six parameters of the Measurement-While- Drilling data and the UCS were considered as input and output parameters respectively. The multiple linear regression (MLR) and the ANN were employed to develop contrast models. The results reveal that the developed GA-ANN hybrid model can predict UCS with higher performance than the ANN and MLR models. This study is of great significance for accurately and effectively evaluating the quality of rock masses in tunnel engineering.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회 2차
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• pp.200-211
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• 2010

Tunnel Mapper, which is tunnel face survey system was used to conduct Face Mapping on the face of the tunnel that is under construction. Then, accuracy and utility value on the forecast of discontinuity were verified to verify the field application in order to present the measures for the use of the system for conducting research on the discontinuity. As result of the directivity verification following discontinuity‘s project, forecasted measurement and actually researched measurement error for the Dip direction and Dip angle was less than ${\pm}10$. Accuracy was 82.6% for Dip direction and 90.7% for Dip angle, which are high. Accordingly, face research discontinuity forecasting system's reliability level towards directivity is high. Tunnel Mapper, a tunnel face survey system can be leveraged to replace face's visual survey and to obtain objective information, enabling execution of the survey system that can automate face survey going beyond time and space related limitations.

• 한국안전학회지
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• 제34권1호
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• pp.1-7
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• 2019

Electromagnetic measurements of the power cable tunnel were conducted from August 10 to 20, 2018, in the ${\bigcirc}{\bigcirc}$ city underground utility tunnel. During this period, the average temperature was $31.89^{\circ}C$ and the humidity was 67.56% in power cable tunnel. As a result of the electromagnetic measurement, the highest electric field was 25.3 V/m and the magnetic flux density was $42.6{\mu}T$. The average electric field was 18.56 V/m and the magnetic flux density was $29.32{\mu}T$ in the power cable tunnel. As a result of comparison with the electric equipment technical standard, the electric field in the power cable tunnel was 0.5% of the electric equipment standard and 35.2% of the magnetic flux density. It's similar value that electric field is about robotic vacuum(15.53 V/m), and magnetic flux density is similar value about capsule- type coffee machine ($23.07{\mu}T$). The number of cable lines and the size of the electromagnetic waves were not proportional to each other through comparison of cable lines in the power cable tunnel. It was confirmed that 154 kV, rather than 22.9 kV, could have a greater influence on occupational.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.1350-1357
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• 2010

In tunnelling, temporary ventilation is very important factor in the safety of worker and the work efficiency which is affected by visibility. There are a lot of problems in the recent tunnel construction, because the longer the tunnel, the more the present design doesn't satisfy the allowable standard about dust and air pollution. Especially, In case the length of tunnel is more than 1,000m, the ventilation efficiency tends to decrease. In this study, the field measurement of the degree of contamination was performed near the face of tunnel. Based on the results obtained, the main factors of problem in temporary ventilation are the difference of temperature between outside and inside, the rate of leakage of ventilation duct and the dust and so on. It maybe helpful to the solution of problems, and also the accurate ventilation estimate.

• 대한기계학회논문집
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• 제19권5호
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• pp.1280-1290
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• 1995

In order to investigate the compression wave propagating in a high-speed railway tunnel, a numerical calculation was applied to the wave phenomenon occurring in a model tunnel. Unsteady, one-dimensional inviscid or viscous flows were solved by an explicit TVD scheme, and the calculated flows were compared with the results of measurement in real tunnels. Tunnel noises caused by emission of the compression wave were characterized in terms of excess pressure of compression wave, pressure gradient in the wave front and width of the compression wave. Calculated attenuation, pressure gradient and width of compression wave with the propagating distance agreed with the results of measurement in the real tunnels. The results also show that tunnel noises are proportional to the train velocity entering the tunnel.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 I
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• pp.322-325
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• 2003

In this paper, path loss characteristics in a curved subway tunnel are measured and analyzed. The measurement is carried out in the frequency bands of 2.45GHz and 5.8GHz. A directional antenna is employed for transmission and an omnidirectional antenna for reception. This measurement is performed in the subway tunnel in the vicinity of the Daejon station. The tunnel is curved and its cross section is arch-shaped. The path loss is measured with the location of the transmitter antenna fixed and the receiver antenna moving in the tunnel. The measured path loss ratio is about 0.1dBm/m. Also, the signal received from the antenna located on the outer side of curve in the tunnel experiences weaker path loss.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.1228-1233
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• 2002

This study is aimed to evaluate a tunneling effect in association with the measurement of sound transmission loss. Based on the formulation for sound transmission loss of a finite panel in the presence of tunnel, variations of the sound transmission loss with parameters such as the location of panel and tunnel depth are investigated. It can be seen that differences in the sound transmission loss are quite evident below coincidence frequency and the sound transmission loss greatly depends on panel location in the tunnel. In comparison with the case without a tunnel, maximum difference occurs in the case where the panel is placed on the center of the tunnel and the flushing with the end of the tunnel gives the better estimation of transmission loss.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.749-754
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• 2003

In this paper, we introduce the measurement of the underwater noise with 32channel hydrophone array of Samsung CAvitation Tunnel (SCAT) and the detection technique of noise sources by using the beam-forming method. Measurement and way signal Processing under fluid flow are essential works for the underwater acoustics, especially for the detection of noise sources. As the acoustic impedance of the water is relatively high and the tunnel is an enclosed system, we have to consider the interaction between tunnel and water together with the reflection of noise in the beam-forming technique. Also, for a hydrophone array system that is fixed on one side of tunnel wall as done in SCAT is liable to suffer from some limitations in the detection of the noise sources with the array, we discuss these limitations particularly on the frequency range and spacing of noise sources.

• 한국터널지하공간학회 논문집
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• 제14권2호
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• pp.117-129
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• 2012

본 논문에서는 1995년 서울지하철 5, 7, 8호선 터널구조물에 국내 최초로 설치되어 운영 중에 있는 터널 유지관리 계측시스템에 대한 측정 및 분석주기를 국내 및 국외 적용사례와 국내 터널의 유지관리계측 분석결과 및 시설물안전관리 관계법령기준을 검토하여 향후에 적용할 터널 유지관리계측의 측정 및 분석주기를 설정하고자 연구를 수행하였다. 현재까지의 계측주기로 계측관리를 한 결과 계측주기에 따른 문제는 없는 것으로 판단되었다. 국내 지하철 5, 6호선 4개 터널의 유지관리계측 분석결과 콘크리트 라이닝 응력과 철근응력이 약 45개월 경과시점에서 서서히 수렴하는 것으로 분석되어 계측기 설치 후 약 4년 까지는 계측 측정 및 분석주기를 빈번하게 하고, 4년 이후에는 빈도를 늦추는 것이 타당할 것으로 판단된다.

• 지질공학
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• 제17권4호
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• pp.567-576
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• 2007

디지털 영상을 통한 터널 내공의 3차원 절대변위 계측의 현장 적용성 검토를 위해 OO터널 현장에 계획된 내공변위 계측단면 상에 위치한 광파 타겟의 변위를 측정하고자 하였다. 디지털 영상 계측을 위한 3차원 입체모델 생성을 위해 측정위치마다 3개의 측선까지의 타겟만 고려하였다. 하나의 입체모델의 생성을 위해서 각 위치에서 3장 이상의 디지털 영상을 획득하여 입체모델을 구성하였으며, 마지막 2개 측선에서의 6개 타겟(천단, 좌우 측벽)을 계속 중첩시켜가며 다음 입체 모델을 구성하여 6개 이상의 정합점이 두 입체모델에서 공유될 수 있도록 하였다. 광파 계측과 디지털 영상계측을 통한 터널 시공 중 암반의 3차원 절대변위 계측 방법을 비교하기 위해 10회에 걸쳐 디지털 영상 계측과 광파 계측을 동일한 구간에 동시에 적용하였다. 각 방법을 사용한 계측에 소요되는 시간과 계측결과를 비교하였다.