• Computers and Concrete
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• 제21권4호
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• pp.399-406
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• 2018

The present study focuses on the performance of basalt fiber reinforced concrete (BFRC) lining in tunnel situated in sandstone rock when subjected to internal blast loading. The blast analysis of the lined tunnel is carried out using the three-dimensional (3-D) nonlinear finite element (FE) method. The stress-strain response of the sandstone rock is simulated using a crushable plasticity model which can simulate the brittle behavior of rock and that of BFRC lining is analyzed using a damaged plasticity model for concrete capturing damage response. The strain rate dependent material properties of BFRC are collected from the literature and that of rock are taken from the authors' previous work using split Hopkinson pressure bar (SHPB). The constitutive model performance is validated through the FE simulation of SHPB test and the comparison of simulation results with the experimental data. Further, blast loading in the tunnel is simulated for 10 kg and 50 kg Trinitrotoluene (TNT) charge weights using the equivalent pressure-time curves obtained through hydrocode simulations. The analysis results are studied for the stress and displacement response of rock and tunnel lining. Blast performance of BFRC lining is compared with that of plain concrete (PC) and steel fiber reinforced concrete (SFRC) lining materials. It is observed that the BFRC lining exhibits almost 65% lesser displacement as compared to PC and 30% lesser displacement as compared to SFRC tunnel linings.

• 한국암반공학회:학술대회논문집
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• 한국암반공학회 2008년도 국제학술회의
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• pp.43-51
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• 2008

Currently an increasing number of urban tunnels with small overburden are excavated according to the principle of the New Austrian Tunneling Method (NATM). For rational management of tunnels from planning to construction and maintenance stages, prediction, control and monitoring of displacements of and around the tunnel have to be performed with high accuracy. Computational method tools, such as finite element method, have been and are indispensable tool for tunnel engineers for many years. It is, however, a commonly acknowledged fact that determination of input parameters, especially material properties exhibiting nonlinear stress-strain relationship, is not an easy task even for an experienced engineer. Use and application of the acquired tunnel information is important for prediction accuracy and improvement of tunnel behavior on construction. Artificial Neural Network (ANN) model is a form of artificial intelligence that attempts to mimic behavior of human brain and nervous system. The main objective of this paper is to perform the deformation analysis in NATM tunnel by means of numerical simulation and artificial neural network (ANN) with field database. Developed ANN model can achieve a high level of prediction accuracy.

• 설비공학논문집
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• 제19권5호
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• pp.386-393
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• 2007

This paper studies the ventilation characteristics according to the jet fan location at the long road tunnel using the CFD software 'FLUENT' which is based on the finite volume method. The tunnel model used in the analysis has a length of 1600m, a cross sectional area of $120m^3$, and is composed of 3 lanes and one way. The velocity profile, the distribution of CO concentration and the ventilation flow rate within the tunnel are analyzed, respectively. In the analysis, it is found that the dependence of the ventilation flow rate upon the jet fan location is small, but the CO concentration in the tunnel is at the lowest when the jet fans are installed near the tunnel outlet. An air stream right below the jet fan is almost inactive due to the strong stream injection near the jet fan. Thus, the pollution level below the jet fan must be higher than the other area.

• Structural Engineering and Mechanics
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• 제86권5호
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• pp.621-633
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• 2023

Stability analysis and support system estimation of the Beheshtabad water transmission tunnel is investigated in this research. A combination approach based on the rock mass rating (RMR) and rock mass quality index (Q) is used for this purpose. In the first step, 40 datasets related to the petrological, structural, hydrological, physical, and mechanical properties of tunnel host rocks are measured in the field and laboratory. Then, RMR, Q, and height of influenced zone above the tunnel roof are computed and sorted into five general groups to analyze the tunnel stability and determine its support system. Accordingly, tunnel stand-up time, rock load, and required support system are estimated for five sorted rock groups. In addition, various empirical relations between RMR and Q i.e., linear, exponential, logarithmic, and power functions are developed using the analysis of variance (ANOVA). Based on the significance level (sig.), determination coefficient (R²) and Fisher-test (F) indices, power and logarithmic equations are proposed as the optimum relations between RMR and Q. To validate the proposed relations, their results are compared with the results of previous similar equations by using the variance account for (VAF), root mean square error (RMSE), mean absolute percentage error (MAPE) and mean absolute error (MAE) indices. Comparison results showed that the accuracy of proposed RMR-Q relations is better than the previous similar relations and their outputs are more consistent with actual data. Therefore, they can be practically utilized in designing the tunneling projects with an acceptable level of accuracy and reliability.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 봄 학술발표회 논문집
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• pp.309-314
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• 1999

In this paper, an application of finite element procedure fur tunnel failure analysis has been studied. The numerical model is applied to the simulation of a series of plane strain laboratory tests on the small scale model of a shallow tunnel. By comparing experimental and numerical results some conclusions are drawn on the effectiveness of the numerical approach. The findings from these numerical experiments show relative differences in the pattern of failure behaviour for shallow tunnels.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 춘계학술대회 논문집
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• pp.495-502
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• 2000

For the tunnel design of the first class on new Seoul-Chunchon railway, we investigated for train speeds to run through tunnels without ear-discomfort of passenger in cabin by application of numerical analysis. Also we analyzed the effect of the wind speed induced by train in tunnel that is very harmful to the workers on railroad and the effect of the air-pressure fluctuations which get the fatigue to the tunnel lining and the car body.

• 한국터널지하공간학회 논문집
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• 제22권4호
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• pp.451-468
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• 2020

단면이 작게 만들어진 노후화된 터널은 만성적인 교통정체를 유발한다. 이는 터널의 확폭을 통하여 해결할 수 있다. 일반적으로 터널을 확폭할 경우, 기계식 또는 발파식 굴착방법을 통하여 기존터널의 외곽부를 굴착하게 된다. 이러한 굴착은 주변 지반뿐만 아니라 기존터널에도 영향을 미치게 된다. Pre-cutting 공법의 적용은 이러한 문제를 효과적으로 해결할 수 있는 방법이 될 수 있다. 따라서 Pre-cutting을 적용하여 확폭을 수행할 경우, 이에 따른 영향분석은 필수적으로 수행되어야 한다. 본 연구에서는 터널 확폭에서 Pre-cutting을 적용할 경우, 이에 따른 영향을 분석하기 위하여 6가지의 지반등급에서 수치해석을 수행하였다. 해석에서는 확대차로와 Pre-cutting의 굴착길이를 변수로 하여 수행하였으며, 기존터널과 확폭터널의 천단침하에 주목하여 분석하였다. 그 결과, 확폭터널의 천단침하는 확폭이 완료가 되면, Pre-cutting의 굴착 길이와 상관 없이 동일한 값으로 수렴하는 것을 확인하였다. 기존터널의 경우, 굴진면의 전방 5 m 내에서 융기가 발생하였으며, Pre-cutting의 굴착 길이가 짧을수록 융기 발생 예방에 효과적인 것으로 나타났다.

• 한국지반환경공학회 논문집
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• 제13권12호
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• pp.81-89
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• 2012

도심지 내에서 교통량 증가로 인하여 차선확대가 요구되는 경우, 기존 터널은 증가된 차선만큼 단면을 확대할 필요가 있다. 터널 단면확대 공사로 발생되는 터널주변의 교통정체를 해소하기 위하여 터널 내에 직사각형 단면의 프로텍터를 설치하여 프로텍터 내부로 교통흐름을 유지하기도 한다. 프로텍터를 사용하면 터널 측벽 하부에서 프로텍터와 굴착 면 사이의 공간이 협소하여 록볼트 시공이 불가능할 수도 있다. 본 연구에서는 터널 측벽 하부의 협소한 공간에서 록볼트를 시공하지 않고 숏크리트 두께를 증가시켜 터널의 안정성을 확보하는 방법을 제안하였다. 기존 2차선 재래식 터널을 3차선 및 4차선 NATM터널로 확대 시공할 경우에 대하여 수치해석을 수행하였다. 터널 측벽 하부에 록볼트를 시공한 경우, 록볼트를 시공하지 않은 경우 및 록볼트를 시공하지 않고 숏크리트 두께만 증가시킨 경우에 대하여 터널의 천단변위, 내공변위 및 숏크리트에 발생한 응력을 비교분석하였다. 천단변위 및 상반 내공변위는 차이가 거의 없었으며, 하반 내공변위는 터널 측벽 하부에 록볼트를 시공하지 않은 경우가 록볼트를 시공한 경우보다 최대 1.3mm 크게 발생하였다. 또한 숏크리트에 발생한 휨압축응력은 터널 측벽 하부에 록볼트를 시공하지 않은 경우가 록볼트를 시공한 경우보다 최대 1.3MPa 크게 발생하였다. 록볼트 미시공에 의해 추가 발생된 숏트리트 응력을 감소시키기 위하여 기존 숏트리크 두께의 20%(250mm ${\rightarrow}$ 300mm, 4차선 터널)및 25%(200mm ${\rightarrow}$ 250mm, 3차선 터널)를 추가 시공하면 록볼트를 시공할 경우와 비슷한 응력수준을 나타내는 것으로 분석되었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1993년도 봄 학술회 논문집
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• pp.1-8
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• 1993

This paper concerns the analytical concept of tunnel design for the case where the groundwater level remains almost to a standstill even though the steady state groundwater flow occurs through tunnel drainage systems. The effect of the seepage force is considered in analysis. Two case strudies are made : the one the round shape tunnel ; the other the horse shape. The design moments, shear forces and axial forces are calculated and these results are compared to the case of water proof tunnel design as well as the case of the tunnel design without groundwater consideration.

• 한국터널지하공간학회 논문집
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• 제5권1호
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• pp.43-54
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• 2003

현재 복개 터널구조물의 해석 및 설계에는 구조공학적 모델링 기법이 널리 적용되고 있으나, 이러한 구조공학적 모델링 기법은 지형적인 영향인자 및 soil arching 등과 같은 지반공학적 측면의 영향인자를 고려하기에 많은 어려움이 있다. 따라서, 본 연구에서는 복개 터널구조물의 합리적이고 경제적인 설계를 위하여 복개 터널구조물의 거동에 영향을 미치는 인자로써 콘크리트 라이닝과 성토체의 계면요소, 굴착사면의 경사, 이격거리 및 성토사면 등을 고려하여 지반공학적 모델링 기법을 이용한 수치해석 수행하였다. 이의 결과를 토대로 각 영향인자 변화에 따른 복개 터널구조물의 역학적 거동특성을 분석하였다.