• Journal of Korean Tunnelling and Underground Space Association
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• v.9 no.1
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• pp.19-28
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• 2007

Tunnel management is a time-consuming and expensive task. In particular, visual analysis of tunnel inspection often requires extended time and cost and shows problems on data gathering, storage and analysis. This study proposes a new approach to extract information for tunnel management by using a laser scanning technology. A prototype tunnel laser scanner developed was used to obtain point clouds of a railway tunnel surface. Initial processing of laser scanning data was to separate those laser pulses returned from the installations attached to tunnel liner using radiometric and geometric characteristics of laser returns. Once the laser returns from the installations were separated and removed, physically damaged parts on tunnel lining are detected. Based on the plane formed by laser scanner data, damaged parts are detected by analysis of proximity. The algorithms presented in this study successfully detect the physically damaged parts which can be verified by the digital photography of the corresponding location on the tunnel surface.

• Journal of the Society of Disaster Information
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• v.20 no.1
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• pp.1-12
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• 2024

Purpose: The objective of this study was to improve the tunnel maintenance and monitoring technology by establishing the maintenance, management, and monitoring standards for shield and TBM tunnels, which had been applied more in recent years. Method: This study comprehensively analyzed and compared the data and model simulations of Seoul Subway Lines 7 and 9 and Bundang Line, shield and TBM tunnels in South Korea, tunnels in France and Japan, and Channel Tunnel in the UK. Result: This study set maintenance and monitoring standards when there was no design estimate based on numerical analyses such as section design and section analysis regarding the maintenance and monitoring section of shield and TBM tunnels. Conclusion: It is necessary to determine safety by comprehensively considering not only each monitoring item but also the changing trend and correlation of all items and compensation of the tunnel.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.5
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• pp.749-760
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• 2017

Recently, the proportion of tunnel structures in roads and railways has increased rapidly. Along with this trend, the rate of occurrence of cracks and dropouts in concrete lining of tunnel structures is increasing. Generally, maintenance of such concrete lining is normalized and managed as the core of maintenance work in tunnel maintenance. However, the maintenance of the tunnel pavement is important in securing driver in the tunnel. In the design of tunnels, the underground condition of the tunnel is designed to be in good rock condition, so there have not been many cases of cracks in the tunnel pavement in the past. Recently, the construction of tunnel structures has been rapidly increased, and the length of the tunnels has become longer.Tunnel pavement installed in these ground conditions is increasing the occurrence of cracks in the pavement due to decrease of bearing capacity of the pavement after a long time. In this study, FWD and GPR were conducted to analyze the types of cracks and the reduction of bearing capacity in the tunnel.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.4
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• pp.441-455
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• 2015

In the present study, a face safety monitoring system was developed that will enable judging collapse risks on faces during tunnel construction to secure workers' safety. This system enables detecting abnormal behaviors of faces by analyzing the displacement of faces measured in real time using the x-MR control chart technique. In addition, an algorithm to judge false alarms was developed so that abnormal behaviors of faces and errors occurring in the process of work can be distinguished from each other by comparing the number of measured values exceeding the management criteria and moving range k. The results of the present study are applicable to real-time monitoring of behavior on the face in dangerous ground sections to minimize damage to workers.

• Journal of the Korean GEO-environmental Society
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• v.11 no.8
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• pp.49-55
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• 2010

Safety estimation of the pillar between parallel tunnels are very important considering stress concentration in case the piller width is not enough to secure the stability. Pillar width needs to be determined properly because of the progressive failure-risk of pillar due to stress-concentration. In this research, the effect of element size in numerical analysis was evaluated based on that yield pillar's stability and proposed systematic analysis about pilar's stability examination. In consequence of it, element size does not give any effect on intensity stress ratio. On the other hand, the analysis using the smaller element size results in lower safety factor in strength reduction technique. In case of the weathered re.k on the main ground layer, the analysis of result was not reliable. In conclusion, the smaller element size is, the more stable factor is.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.10a
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• pp.56-65
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• 2006

As portions(28m) of the designed tunnel was crossing the abandoned tunnel, methods for safe construction were demanded. The level of the abandoned tunnel and the designed tunnel was almost same and each tunnel was crossing at an angle of about 40 degrees. Therefore the abandoned tunnel would adversely affect the stability of the designed tunnel. Some sections of the abandoned tunnel passes through the designed tunnel wall were fully filled with tunneling spoil and cement milk grouting to increase tunnelling stability. By checking physical properties of grouting cores drilled at the cross section of the designed tunnel and the abandoned tunnel, the quality of material filled in the abandoned tunnel was confirmed. Also the stability of the designed tunnel was checked by the monitoring during excavation of the tunnel.

• Journal of Korean Tunnelling and Underground Space Association
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• v.7 no.2
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• pp.165-176
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• 2005

A variety of research projects have been undertaken due to the recent catastrophic tunnel fires throughout the world, Among them, more emphasis was given to full scale and scale model fire experiments, and recently the area of fire resistance of tunnel structures attract more interests, On the contrary to the cases in most of the advanced countries where design standards as well as recommendations have already been announced, no local criteria for design can be found, This paper aims at deriving the fire characteristics appropriate for the assessment criteria of fire resistance of structures in local tunnels through studying the existing fire temperature curves including ISO 834 standard temperature curve, HC curve, RWS curve, ZTV curve and EBA curve.

• Journal of Korean Tunnelling and Underground Space Association
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• v.18 no.3
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• pp.319-329
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• 2016

Underground structures such as subsea tunnel having large section should be stable against seismic loads. In general, underground structures show more stable behavior due to the limited dynamic motion and force, and considerable energy dissipation; however, severe damage was reported from recent earthquakes. Therefore, more sophisticated and analytic approach is required to investigate the seismic response of underground structure like subsea tunnel. In this study, seismic analysis of virtual Honam-Jeju subsea tunnel are performed. Consequently, stresses and forces of tunnel lining increased at fractured and/or weak rock zones. Stresses and forces of tunnel lining also increased at large section under axially deformed condition; however, decrease under transversely deformed condition.

• Geotechnical Engineering
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• v.11 no.4
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• pp.125-140
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• 1995

Generally, the groundwater pressure is not considered in the design of concrete lining of bottom drainage tunnel. This design method implies that the phreatic surface is drawdown to the bottom of tullnel. When tile groundwater is continually supplied without changing of groundwater table, there is a possibility at which the groundwater pressure acting on the tunnel lining after the completion of tunnel. Therefore, the safety of tunnel lining must be checked in this case. In this paper, the stability of bottom drainage tunnel which is affected by groundwater discharge is analzed by using of the Finite Element Method at the 2 sections of subway where the groundwater level has a tittle change during the construction. As the result of analysis, the grouting for the water tightness and the permanent monitoring system of tunnel are required for maintaining of long-term stability of bottom drainage tunnel for the case of groundwater plassure acting on the tunnel lining is greater than that of design stage.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.5
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• pp.611-620
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• 2019

The shield tunnel was mostly applied to cable tunnel with a diameter of 3~4 m, recently 7.8 m diameter shield tunnel was constructed in the lower section of the Incheon International Airport runway and is planning or under construction to roads and railway tunnels in the lower section of the Han River. Segments are also becoming larger as the shield tunnel cross-section increases, which causes a number of problems in the design, construction, and performance evaluation of segments. In this study, segment lining structural safety, criteria for serviceability check considering axial forces and quality control method for approximately 8 m in diameter shield tunnel were reviewed by field measurements and full scale bending test.