• Tunnel and Underground Space
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• v.6 no.3
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• pp.197-208
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• 1996

Due to the constraints in pre site-investigation for tunnel, it is essential to redesign the support structures suitable for rock mass conditions such as rock strength, ground water and discontinuity conditions for safe tunnel construction. For the selection of optimum support, it is very important to carry out the rock mass classification and in-situ measurement in tunnelling. In this paper, in a mountain tunnel designed by NATM in hard rock, the selectable system for optimum support has been studied. The tunnel is situated at Chun-an in Kyungbu highspeed railway line with 2 lanes over a length of 4, 020 m and a diameter of 15 m. The tunnel was constructed by drill & blasting method and long bench cut method, designed five types of standard support patterns according to rock mass conditions. In this tunnel, face mapping based on image processing of tunnel face and rock mass classification by RMR carried out for the quantitative evaluation of the characteristics of rock mass and compared with rock mass classes in design. Also, in-situ measurement of convergence and crown settlement conducted about 30 m interval, assessed the stability of tunnel from the analysis of monitoring data. Through the results of rock mass classification and in-situ measurement in several sections, the design of supports were modified for the safe and economic tunnelling.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.03c
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• pp.93-104
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• 2000

By means of analyzing the problems in monitoring plan, design, installation, operation based on maintenance monitoring system installed in subway tunnel section, the methods of improvement were proposed for applying to subway monitoring maintenance effectively in future. The choice of the better monitoring system, the operating method of monitoring system, the confidence and continuity of maintenance monitoring, the performance of responsible monitoring supervision in the phase of the planning of monitoring and design were proposed. The problem and developed plan in the different monitoring systems, the calibration and correction of monitoring system, the analysis for the results and plan for maintenance in the phase of installation of monitoring system and operation were also proposed.

• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.5
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• pp.523-536
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• 2013

In order to ensure the safety of the subsea tunnel during its construction and operation, unlike the underground structures on land, the special monitoring system is essential which considers the characteristics of subsea tunnels in addition to conventional stress and displacement measurements applied to existing land tunnels. Therefore, the concept applied to NATM is reorganized to evaluate the stability of subsea tunnels. And the observation system for making a monitoring plan, the critical strain theory for tunnel safety management and MS monitoring methods for detecting the local failure and crack initiation of rock and supports, are introduced. Finally, the scheme of monitoring and management for subsea tunnels by using these methods is suggested.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.869-875
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• 2009

Safety is a big issue in the construction sites. For safe and secure management, tracking locations of construction resources such as labors, materials, machineries, vehicles and so on is important. The materials, machineries and vehicles could be controlled by computer, whereas the movement of labors does not have fixed pattern. So, the location and movement of labors need to be monitored continuously for safety. In general, Global Positioning System(GPS) is an opt solution to obtain the location information in outside environments. But it cannot be used for indoor locations as it requires a clear Line-Of-Sight(LOS) to satellites Therefore, indoor location monitoring system could be a convenient alternative for environments such as tunnel and indoor building construction sites. This paper presents a case study to investigate feasibility of Wi-Fi based indoor location monitoring system in construction site. The system is developed by using fingerprint map of gathering Received Signal Strength Indication(RSSI) from each Access Point(AP). The signal information is gathered by Radio Frequency Identification (RFID) tags, which are attached on a helmet of labors to track their locations, and is sent to server computer. Experiments were conducted in a shield tunnel construction site at Guangzhou, China. This study consists of three phases as follows: First, we have a tracking test in entrance area of tunnel construction site. This experiment was performed to find the effective geometry of APs installation. The geometry of APs installation was changed for finding effective locations, and the experiment was performed using one and more tags. Second, APs were separated into two groups, and they were connected with LAN cable in tunnel construction site. The purpose of this experiment was to check the validity of group separating strategy. One group was installed around the entrance and the other one was installed inside the tunnel. Finally, we installed the system inner area of tunnel, boring machine area, and checked the performance with varying conditions (the presence of obstacles such as train, worker, and so on). Accuracy of this study was calculated from the data, which was collected at some known points. Experimental results showed that WiFi-based indoor location system has a level of accuracy of a few meters in tunnel construction site. From the results, it is inferred that the location tracking system can track the approximate location of labors in the construction site. It is able to alert the labors when they are closer to dangerous zones like poisonous region or cave-in..

• Journal of Korean Society of Disaster and Security
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• v.7 no.2
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• pp.9-16
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• 2014

Though the maintenance monitoring of structurally weak parts of the tunnel structure in public service must be judged in connection with the monitoring during the construction period for analysis of the behavior of the ground and surrounding structures following the tunnel excavation for the effective management, the monitoring during the construction period and the maintenance monitoring are implemented separately on the basis of the periods of construction and maintenance, so the connectivity and systematic management of the related data are mostly inadequate. The improvement direction is suggested in this thesis, by analyzing the problems of tunnel monitoring in the domestic design criteria. And, it is anticipated that from now on the use of hi-tech sensors and wireless communications technology will proceed vigorously in the maintenance, so considering these situations, the development and application of the maintenance monitoring system and the revision of the domestic design criteria and specification are needed in the future.

• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.255-261
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• 2003

Tunnelling in poor and heterogeneous ground is a difficult task. Even with a good geological investigation, uncertainties with respect to the local rock mass structure will remain. Especially for such conditions, a reliable short-term prediction of the conditions ahead and outside the tunnel profile are of paramount importance for the choice of appropriate excavation and support methods. The information contained in the absolute displacement monitoring data allows a comprehensive evaluation of the displacements and the determination of the behaviour and influence of an anisotropic rock mass. Case histories and with numerical simulations show, that changes in the displacement vector orientation can indicate changing rock mass conditions ahead of the tunnel face (Schubert & Budil 1995, Steindorfer & Schubert 1997). Further research has been conducted to quantify the influence of weak zones on stresses and displacements (Grossauer 2001). Sellner (2000) developed software, which allows predicting displacements (GeoFit$\circledR$). The function parameters describe the time and advance dependent deformation of a tunnel. Routinely applying this method at each measuring section allows determining trends of those parameters. It shows, that the trends of parameter sets indicate changes in the stiffness of the rock mass outside the tunnel in a similar way, as the displacement vector orientation does. Three-dimensional Finite Element simulations of different weakness zone properties, thicknesses, and orientations relative to the tunnel axis were carried out and the function parameters evaluated from the results. The results are compared to monitoring results from alpine tunnels in heterogeneous rock. The good qualitative correlation between trends observed on site and numerical results gives hope that by a routine determination of the function parameters during excavation the prediction of rock mass conditions ahead of the tunnel face can be improved. Implementing the rules developed from experience and simulations into the monitoring data evaluation program allows to automatically issuing information on the expected rock mass quality ahead of the tunnel.

• Journal of Korean Tunnelling and Underground Space Association
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• v.9 no.3
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• pp.229-240
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• 2007

The 3D absolute displacement monitoring system has been developed to analyze the tunnel convergence measured under construction of underground structures and to manage effectively the measured data. The system is comprised of the total station, the anchor-typed target pin and the 3D absolute displacement measurement and management program. In this paper, the types and specifications of the 3D total station were presented. The anchor-typed target pin, an improved model of traditional one, was developed and its sightable distance and measurement accuracy were checked by field tests. Also a 3D absolute displacement measurement and management program, TEMS 3D, was developed to provide some analysis tools including the trend and influence lines. L/C ratio, S/C ratio and the like. The developed system was applied the construction stage of a railway tunnel for testing purpose. It is verified that the developed system is capable of predicting weak zones ahead of tunnel face by comparing with results of TSP (Tunnel Seismic Prediction) survey.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.11
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• pp.1879-1884
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• 2007

In the electric power industry, it is important that the supply of energy must be guaranteed. Many power utilities control and supervise the transmission line to avoid power failures. In case of underground tunnel, some troubles are reported in cable joint. To stabilize the power, it is needed to monitor the cable joint. Many researches of cable joint monitoring have been going on by partial discharge measurement and temperature measurement using optical cable. These methods need much cost to install and maintain, so it is only used in critical transmission line. In this research, we use wireless sensor technology, because of its low cost and easy installation. We develop the temperature monitoring system for cable joint. Temperature sensor is installed on the surface of cable joint and sends data to server through router node using wireless network. Generally Ad hoc routing is searched in wireless network. However, in this research, we design the static linear routing mechanism, which is suitable for electric power line monitoring and analyze the life time of the sensor node by measuring the amount of the battery consumption.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.349-350
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• 2015

Traditional power tunnel monitoring and diagnosis system provides simple alert in accordance with limits which set by operator using various field installed various sensor measurements. System's algorithm is too simple and it has uncertainty of sensor with error. In this paper, proposed algorithm give operator verification using installed sensor measurements such as environmental sensors for fire prevention because of cable overheat in the power tunnel.

• Smart Structures and Systems
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• v.6 no.3
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• pp.239-262
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• 2010

Tube Lines has carried out a "knowledge and investigation programme" on the deep tube tunnels comprising the Jubilee, Northern and Piccadilly lines, as required by the PPP contract with London Underground. Many of the tunnels have been in use for over 100 years, so this assessment was considered essential to the future safe functioning of the system. This programme has involved a number of generic investigations which guide the assessment methodology and the analysis of some 5,000 individual structures. A significant amount of investigation has been carried out, including ultrasonic thickness measurement, detection of brickwork laminations using radar, stress measurement using magnetic techniques, determination of soil parameters using CPT, pressuremeter and laboratory testing, installation of piezometers, material and tunnel segment testing, and trialling of remote photographic techniques for inspection of large tunnels and shafts. Vibrating wire, potentiometer, electro level, optical and fibre-optic monitoring has been used, and laser measurement and laser scanning has been employed to measure tunnel circularity. It is considered that there is scope for considerable improvements in non-destructive testing technology for structural assessment in particular, and some ideas are offered as a "wish-list". Assessment reports have now been produced for all assets forming Tube Lines' deep tube tunnel network. For assets which are non-compliant with London Underground standards, the risk to the operating railway has to be maintained as low as reasonably practicable (ALARP) using enhanced inspection and monitoring, or repair where required. Monitoring techniques have developed greatly during recent years and further advances will continue to support the economic whole life asset management of infrastructure networks.