• Geomechanics and Engineering
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• v.28 no.2
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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.

• Journal of Korean Society of societal Security
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• v.2 no.1
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• pp.57-64
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• 2009

With the increase in construction of long railway tunnel, social interest in the railway tunnel fire risk has also increased. However, quantitative fire risk research on this topic is still lacking, especially in terms of consideration of uncertainty of each variables used in risk analysis. Hence, in this study, to improve the overall performance of fire risk analysis technique for railway tunnel, Monte-Carlo simulation method is added to the traditional probabilistic risk analysis based on event tree approach and its validity is investigated by applying it to the real railway tunnel project.

• Journal of Korean Tunnelling and Underground Space Association
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• v.9 no.3
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• pp.287-298
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• 2007

Recently, as the construction of new railway and the relocation of existing line increase, tunnel structures get longer. The railway fire accidents in long tunnel bring large damages of human life and disaster. The interest on safety in long tunnel has been growing and the safety standard for long tunnels is tightening. For that reason, at the planning stage of a long tunnel, the optimum design of safety facility for minimizing the risks and satisfying the safety standard is required. For the reasonable design of a long railway tunnel considering high safety, qualitative estimation for tunnel safely is required. In this study, QRA (Quantitative Risk Analysis) technique is applied to design of a long railway tunnel for assuring the safety function and estimating the risk of safety. The case study for safety design was carried out to verify the QRA technique for two railway tunnels.

• Journal of Korean Tunnelling and Underground Space Association
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• v.8 no.4
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• pp.377-388
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• 2006

Most structures experience deterioration after construction. A routine inspection and maintenance must be accomplished for the efficient use of the structures. The routine inspection will play a major role on the determination of maintenance period and method. This study aims development of an automated tunnel inspection system based upon a 3 dimensional laser scanner. As for the initial stage of the project, a prototype tunnel scanner has been developed. The development of a tunnel scanner prototype follows comparison between image scanning and laser scanning system and investigation on the applicability and adaptivity of the scanners to the railway tunnel scanner. The applicability of the laser scanner on the railway tunnel has been confirmed from the pilot test by using commercialized general purpose close range laser scanner and applicability of a laser scanner as a railway tunnel scanner has been checked. From the result, a prototype of railway tunnel scanner has been built and the calibration of the system was carried out. Finally the developed tunnel laser scanner has been applied to different shapes and sizes of tunnels in use.

• Smart Structures and Systems
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• v.21 no.5
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• pp.537-548
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• 2018

A tunnel deformation monitoring system is developed with the use of fiber Bragg grating (FBG) sensing technique, aiming at providing continuous monitoring of railway tunnel deformation in the long term, and early warning for the rail service maintainers and authorities to avoid catastrophic consequences when significant deformation occurs. Specifically, a set of FBG bending gauges with the ability of angle measurement and temperature compensation is designed and manufactured for the purpose of online monitoring of tunnel deformation. An overall profile of lateral tunnel displacement along the longitudinal direction can be obtained by implementing an array of the FBG bending gauges interconnected by rigid rods, in conjunction with a proper algorithm. The devised system is verified in laboratory experiments with a test setup enabling to imitate various patterns of tunnel deformation before the implementation of this system in an in-service high-speed railway (HSR) tunnel.

• Journal of KIBIM
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• v.9 no.1
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• pp.1-10
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• 2019

In process of creating BIM model for tunnel, many user use still CAD, so the workflow for BIM design is not perfect. Therefore, in this paper, we proposes a method to automatically create BIM model without converting 2D drawings in tunnel design. It can allow engineers to design BIM-based tunnel with maximum use of linear information and modify the BIM model whenever there is changed linear information. To do this, we use Dynamo, which can reduce the time required for creating and modifying BIM models during design changes, saving time wasted for BIM conversion design.

• Tunnel and Underground Space
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• v.17 no.2 s.67
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• pp.152-164
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• 2007

Recently as increasing the amounts of cargoes and passengers, it is necessary to improving railway capacity and speed. So the constructions of improving the existing railway line have been advanced. Sometimes the new railway tunnel is built to adjacent the existing railway line. Furthermore the new tunnel might be built near the existing facility within the tunnel width. In this case, it should be analyzed the influence of existing tunnel and if it is necessary, it should be taken the appropriate counterplan. The major analysis contents are follows. One is the influence on the existing tunnel by a blasting and train vibration and the other is stability problem of the existing tunnel by excavation of new tunnel. Therefore, we peformed the following analysis. Refer to a domestic and foreign standard and paper, the permitting level of blasting vibration is decided and the excavation plan of the new tunnel are designed. The numerical analysis is performed about the stability of the existing tunnel and new tunnel. The influence of the train vibration on tunnel is analyzed by the empirical equation.

• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.4 s.56
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• pp.107-115
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• 2009

The number of railway tunnel design is increasing recently compare to a great number of highway tunnel design which had increased with a lot of highway construction in the 70's and 80's. Therefore, there is more or less difference of time between highway tunnel and railway tunnel. In this paper, numerical analysis on two kinds of tunnels, such as two-forked road highway ventilation tunnel and double track railway tunnel with 4.3m of center line, in cases of with support materials condition and without support materials condition were conducted. Finally, stability of two kinds of tunnels were compared and analyzed through comparing of principal stresses and deviator stresses in the near base rock of tunnels using results of numerical analysis.

• Structural Engineering and Mechanics
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• v.57 no.1
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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.

• Journal of the Korean Society for Railway
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• v.14 no.4
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• pp.364-369
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• 2011

For the safety management of tunnel, effective measurements should be continuously carried out. Most of sensors currently being applied for tunnels measure only the local status, thus many of them are needed to monitor an entire tunnel. For the railway tunnel where trains of same conditions are regularly operated, dynamic responses of tunnel structure to train operations can be a good index to estimate the deformation of tunnel structure in wide area. Meanwhile, the electromagnetic interference caused by overhead centenary in railway tunnel obstructs the use of electric-based sensors. In this study a brand new accelerometer using FBG optical fiber sensors is developed to solve these problems. Sensitivity and capacity of the accelerometer are enhanced with effective structural design of its components and verified with laboratory tests. A case history where the developed accelerometers were applied to a safety monitoring system of a high-speed train tunnel is presented. The performances of the developed accelerometers are validated from the measured acceleration data.