• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1993년도 가을 학술발표회논문집
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• pp.32-37
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• 1993

A method of tunnel analysis for a new type of tunnel construction method (ACLCM, Automatic Concrete Lining Construction Method) is presented here. ACLCM is an unique tunnel construction method which provides concrete lining at the end of shield machine by extruding concrete into the space between the excavated ground surface and the inner form (Automatic Concrete Lining Machine). Since behaviors of tunnel and the surrounding soils are greatly influenced by the construction method, existing tunnel design methods may not be applicable to the design of ACLCM tunnel. In this study, a method of ACLCM tunnel analysis is suggested to provide the prediction of behavior of ACLCM tunnel and surrounding soils as well as to check up the safety during the construction and after the completion of ACLCM tunnel

• Structural Engineering and Mechanics
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• 제57권1호
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• pp.1-20
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• 2016

On the basis of the geological conditions of high and steep mountainous slope on which an exit portal of an express railway tunnel with a bridge-tunnel combination is to be built, the composite structure of the exit portal with a bridge abutment of the bridge-tunnel combination is presented and the stability of the slope on which the express railway portal is to be built is analyzed using three dimensional (3D) numerical simulation in the paper. Comparison of the practicability for the reinforcement of slope with in-situ bored piles and diaphragm walls are performed so as to enhance the stability of the high and steep slope. The safety factor of the slope due to rockmass excavation both inside the exit portal and beneath the bridge abutment of the bridge-tunnel combination has been also derived using strength reduction technique. The obtained results show that post tunnel portal is a preferred structure to fit high and steep slope, and the surrounding rock around the exit portal of the tunnel on the high and steep mountainous slope remains stable when rockmass is excavated both from the inside of the exit portal and underneath the bridge abutment after the slope is reinforced with both bored piles and diaphragm walls. The stability of the high and steep slope is principally dominated by the shear stress state of the rockmass at the toe of the slope; the procedure of excavating rockmass in the foundation pit of the bridge abutment does not obviously affect the slope stability. In-situ bored piles are more effective in controlling the deformation of the abutment foundation pit in comparison with diaphragm walls and are used as a preferred retaining structure to uphold the stability of slope in respect of the lesser time, easier procedure and lower cost in the construction of the exit portal with bridge-tunnel combination on the high and steep mountainous slope. The results obtained from the numerical analysis in the paper can be used to guide the structural design and construction of express railway tunnel portal with bridge-tunnel combination on high and abrupt mountainous slope under similar situations.

• 한국터널지하공간학회 논문집
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• 제19권2호
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• pp.231-248
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• 2017

서울시는 도심지 교통체증을 해결하기 위해 최근 경부고속도로의 일부 구간을 복층터널로 계획하는 방안을 검토하고 있다. 도심지에 복층터널을 건설할 경우, 교통난 해소뿐만 아니라 말레이시아 스마트 터널과 같이 홍수 시 침수방지를 위한 저류시설로도 활용할 수 있을 것으로 본다. 그러나 도로터널을 복층터널로 계획할 경우에는 각 지역을 연결하는 분기터널이 필요하며, 분기터널은 토피가 낮은 구간에 편평율이 큰 대단면 또는 복잡한 터널 단면형상으로 이루어지게 된다. 이때 토피가 낮은 지역에서는 지하 공동구나 건물 기초 등에 인접하여 위치하게 되며 터널 건설로 인해 지장물에 미치는 영향에 대해 반드시 검토해야 한다. 본 연구에서는 복층터널에서 분기되는 터널 굴착 시, 지하 공동구에 미치는 영향을 수치해석을 통해 분석하였다. 변위조절모델(Displacement Controlled Model)을 이용하여 터널 주변의 지반손실률을 1.0%, 3.0%, 그리고 5.0%까지 모사하였다. 복층터널에서 분기되는 각도를 $45^{\circ}$와 $36^{\circ}$로 다르게 설정하여 공동구 측면 및 하부로의 접근을 고려할 수 있도록 하였다. 그 결과, 일반적으로 분기터널이 공동구에 근접할수록 그리고 지반손실률이 클수록 변위, 각변위 그리고 안정성에 미치는 영향이 큰 것으로 타나났다. 공동구 바닥부의 침하와 공동구 부재의 안정성에는 이격거리 보다는 공동구의 하부에 근접하여 큰 변위와 부등침하를 유발할 수 있는 각도 $36^{\circ}$, 이격거리 10 m가 가장 취약한 것으로 나타났다. 본 연구를 통해 근접시공 시 구조물의 안정성 평가를 위한 각변위-거리/직경 관계를 제시하였으며, 지하 공동구 안정성에 영향을 미치는 한계 임계 지반손실률을 산정하였다.

• Geomechanics and Engineering
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• 제31권3호
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• pp.237-248
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• 2022

Nowadays, more and more subway tunnels were planed and constructed underneath the ground of urban cities to relieve the congested traffic. Potential damage may occur in existing tunnel if the new tunnel is constructed too close. So far, previous studies mainly focused on the tunnel-tunnel interactions with circular shape. The difference between circular and horseshoe shaped tunnel in terms of deformation mechanism is not fully investigated. In this study, three-dimensional numerical parametric studies were carried out to explore the effect of different tunnel shapes on the complicated tunnel-tunnel interaction problem. Parameters considered include volume loss, tunnel stiffness and relative density. It is found that the value of volume loss play the most important role in the multi-tunnel interactions. For a typical condition in this study, the maximum invert settlement and gradient along longitudinal direction of horseshoe shaped tunnel was 50% and 96% larger than those in circular case, respectively. This is because of the larger vertical soil displacement underneath existing tunnel. Due to the discontinuous hoop axial stress in horseshoe shaped tunnel, significant shear stress was mobilized around the axillary angles. This resulted in substantial bending moment at the bottom plate and side walls of horseshoe shaped tunnel. Consequently, vertical elongation and horizontal compression in circular existing tunnel were 45% and 33% smaller than those in horseshoe case (at monitored section X/D = 0), which in latter case was mainly attributed to the bending induced deflection. The radial deformation stiffness of circular tunnel is more sensitive to the Young's modulus compared with horseshoe shaped tunnel. This is because of that circular tunnel resisted the radial deformation mainly by its hoop axial stress while horseshoe shaped tunnel do so mainly by its flexural rigidity. In addition, the reduction of soil stiffness beneath the circular tunnel was larger than that in horseshoe shaped tunnel at each level of relative density, indicating that large portion of tunneling effect were undertaken by the ground itself in circular tunnel case.

• 한국지반공학회논문집
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• 제28권4호
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• pp.79-89
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• 2012

본 논문은 터널 굴착시 막장면 안정성 확보를 위한 막장폐합비에 따른 막장면 응력 및 지반거동을 분석하기 위해 실내모형실험 및 수치해석적 분석을 실시하였다. 실내모형실험에서는 터널막장면의 폐합비와 토피고에 따른 막장면 응력 및 지반의 거동을 실험하였다. 실내모형실험 결과를 검증하기 위하여 2차원 수치해석을 실시하였으며 이들 서로의 결과들을 비교 분석하였다. 그 결과 막장 폐합비가 증가할수록 터널 막장면 안정성 확보가 가능할 것으로 판단되며 막장 폐합비가 80% 이상일 경우에는 막장 안정성에 큰 문제가 없는 것으로 나타났다. 이러한 연구결과는 향후 경제적인 터널 막장폐합시스템을 개발하는데 매우 유용할 것으로 기대된다.

• Geomechanics and Engineering
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• 제28권2호
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• pp.145-155
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• 2022

Safety is a most important parameters in underground railway transportation; Also stability of underground tunnel is very important in tunneling engineering. Design of a reliable support system requires an evaluation of both ground demand and support capacity. Iran's traditional railway tunnels are mainly supported with masonry structures or unsupported in high quality rock masses. A decrease in rock mass quality due to changes in groundwater regime creep and fatigue in rock and similar phenomena causes tunnel safety to decrease during time. The case study is an old tunnel in Iran, called "Keshvar"; it is more than 50 years old railway organization. In operating this Tunnel, until the several problems came up based on stability and leaking water. The goal of study is evaluation of the various reinforcement systems for supporting of the tunnel. The optimal selection of the reinforcement system is examined using TOPSIS Fuzzy method in light of the looming and available uncertainties. Several factors such as; the tunnel span, maintenance, drainage, sealing, ventilation, cost and safety were based to choose the method and system of designing. Therefore, by identifying these parameters, an optimal reinforcement system was selected and introduced. Based on optimization system for analysis, it is revealed that the systematic rock bolts and shotcrete protection had a most appropriate result for these kind of tunnel in Iran.

• 한국도로학회논문집
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• 제16권3호
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• pp.51-57
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• 2014

PURPOSES : This study is to suggest tunnel length to spray curing compound, based on the field tests. METHODS : At first field test, length from the entrance of tunnel to wet wall was checked by visual survey. The second and third test, various sensors were installed in concrete or in tunnel, such as RH sensor, temperature sensor, portable weather station and etc.. And also, test for bleeding and retaining water of concrete were conducted to evaluate environmental effect on concrete pavement. RESULTS : The result of the field experiment for tunnel length to spray curing compound indicates that length changes depending on tunnel length, season, and location. Environmental condition of a short tunnel was not much different between location near entrance and at center of tunnel. However, in case of a medium and long tunnel, effect of outside environmental condition decreased, when location moved into tunnel center of it. CONCLUSIONS : From the testing results, it can be proposed that optimum tunnel length to spray curing compound is 60m for a medium and long tunnel, and whole length for a short tunnel.

• 터널과지하공간
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• 제23권2호
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• pp.120-129
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• 2013

터널시공 중 발생한 변위를 설계단계에서 설정한 계측관리 기준변위와 비교하여 터널의 안정성을 평가할 때에는 터널막장 후방뿐만 아니라 전방에서 발생하는 변위를 포함한 총변위를 이용하여야 한다. 터널 시공 중 발생하는 총변위를 알기 위하여 터널막장에서 전방을 향해 수평경사계를 설치하여 지중침하를 계측하였고 터널 막장 후방에서는 천단침하계를 이용하여 터널의 천단침하를 계측하였다. 이를 통하여 터널시공 중 발생하는 총천단침하를 계측할 수 있었고 터널막장 전후방 종단선상의 침하곡선 특성도 분석하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 춘계학술대회논문집; 경주코오롱호텔; 22-23 May 1997
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• pp.627-635
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• 1997

In general, the booming noise intensity at tunnel exit is strongly related to the gradient of the compression wave front created by high speed train entering the tunnel. This paper presents some results in relation with the compression wave front produced when the high speed train enters a tunnel. Four kinds of tunnel entrance shape with real dimensions were studied to investigate the formation of compression wave front inside tunnel by train entering tunnel. Computations were carried out using three-dimensional compressible Euler equation with vanishing viscosity and conductivity of fluid. According to the reslts, the flow disturbance occured at tunnel entrance were eliminated by tunnel hood with same cross sectional area. The compression wave front is formed completely at 30-40m from tunnel entrance. The maximum pressure gradient of compression wave front is reduced by 29.8% for the inclined tunnel hood and reduced by 21.5% for the tunnel hood with holes at the top face with tunnel without hood. The length of the inclined hood is 15m and the length of the hood with holes is 20m.

• Geomechanics and Engineering
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• 제22권4호
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• pp.291-303
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• 2020

The deformation of the rock surrounding a tunnel manifests due to the stress redistribution within the surrounding rock. By observing the deformation of the surrounding rock, we can not only determine the stability of the surrounding rock and supporting structure but also predict the future state of the surrounding rock. In this paper, we used grey system theory to analyse the factors that affect the deformation of the rock surrounding a tunnel. The results show that the 5 main influencing factors are longitudinal wave velocity, tunnel burial depth, groundwater development, surrounding rock support type and construction management level. Furthermore, we used seismic prospecting data, preliminary survey data and excavated section monitoring data to establish a neural network learning model to predict the total amount of deformation of the surrounding rock during tunnel collapse. Subsequently, the probability of a change in deformation in each predicted section was obtained by using a Bayesian method for detecting change points. Finally, through an analysis of the distribution of the change probability and a comparison with the actual situation, we deduced the survey mark at which collapse would most likely occur. Surface collapse suddenly occurred when the tunnel was excavated to this predicted distance. This work further proved that the Bayesian method can accurately detect change points for risk evaluation, enhancing the accuracy of tunnel collapse forecasting. This research provides a reference and a guide for future research on the probability analysis of tunnel collapse.