• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.1
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• pp.49-59
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• 2019

In this study, the durability of conical pick cutter was compared and analyzed by pre- and post-test visual inspection, measurement of weight loss and wear volume through field test on two types of conical pick cutters applied to rotary drum cutter. In the visual inspection, it was found that only 9 inserts were lost in the slim type conical pick cutter. This result show that the thickness of the head cover surrounding a insert was important to maintain the insert during excavation. The weight loss and wear volume of the heavy type conical pick cutter were less than half that of the slim type. From these results, it can be confirmed that heavy type is more useful than slim type in hard rock. It should be noted that, when determining the wear loss of the conical pick cutter, the mutual comparison of the weight measurement and the wear volume measurement results may be different due to the unit weight of the material and the spalling caused by excavation.

• Tunnel and Underground Space
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• v.28 no.6
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• pp.513-527
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• 2018

The Tunnel Boring Machine(TBM) is relatively insufficient to cope with unpredicted changes in ground conditions as compared with Conventional Tunnelling Methods. Therefore, it is very important to predict the TBM performance at the design stage and estimate the advance rate for the calculation of the construction period. In this study, we added data to 211 TBM databases constructed in the previous study and analyzed the correlation between TBM outer diameter, maximum thrust, maximum cutterhead torque, cutterhead driving power and RPM, which are the main design and manufacturing specifications of TBM. As a result of the analysis from results obtained in the previous studies, it was confirmed that TBM outer diameter is very effective and important in estimating maximum thrust, maximum cutterhead torque, and cutterhead driving power of the TBM. As a result of comparing the regression equations derived from other TBM databases outside the country and the regression equation obtained from the present study results, the maximum thrust showed a similar tendency to each other, but the maximum torque estimated from the regression equation of this study was higher than that of other countries in the case of the large scale TBM.

• Fire Science and Engineering
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• v.15 no.4
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• pp.71-77
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• 2001

The pipes and cables buried below ground which may have helped to improved city landscapes is becoming direct and indirect cause for various disaster in Korea due to potential possibility of fire. Various types of fire in utility tunnels should be analysed in order to improve its fire safety level, therefore mail problems and shortcomings are checked out as a result of this analysis. By performing both tunnel fire risk analysis and fire safety level comparison in advanced countries, effective measure and approach to required standardization may be presented to bath tunnel structure and its containing cables in order to diminished up to a desirable rate in a near future.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.183-186
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• 2001

For a long time, the ocean was regarded as unknown area ruled by god, consequently, not so much things were developed in scientific methods and activities. Despite a rapid development of geographic information systems(GIS) marine and ocean fields still remained in the scope of traditional tools and intuitive experiences by the late of 1990. However, land based concepts and technology models require additional customization to apply GIS effectively in marine domains, which are resulted from her dynamic, complex and seamless massive nature. This paper gives a brief review of marine spatial data characteristics and also presents strategic approaches to meet the unique marine GIS requirements.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.3
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• pp.601-606
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• 2019

The lenticular Location Based System is related to a location information technology. The system enables users to inform their location in real time wherever in a room, a building, a ship, a basement. In this paper, we analyze limitations and problems of the existing indoor Positioning System and propose a method of user-oriented location service. The proposed method consists of a lenticular sticker, a database(DB) acquisition and analysis technology. The proposed system can be used as an infrastructure to implement various indoor location-based services. In addition to improve user centered positioning accuracy through the development of location-based systems using indoor lenticular systems, it can be used in a disaster situation.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.194-194
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• 2021

최근 지구온난화 및 이상기후 현상으로 인하여 집중호우의 빈도와 강도가 급증하고 있다. 그리고 급격한 도시화로 불투수 면적이 증가하여 도시지역에 침수피해가 빈번하게 발생하고 있는 실정이다. 이러한 침수피해를 방지하기 위하여 침수위험지구, 재해위험지구를 선정하여 집중호우에 대하여 집중관리를 하고 있지만 위험지구이외의 곳에서 침수가 발생할 경우 신속하게 대처하지 못하는 문제가 발생하고 있다. 또한, 하천이 범람하여 발생하는 외수침수의 경우 수위를 실시간으로 확인할 수 있어 미리 대응이 가능하지만, 내수침수의 경우 지하에 매설되어 있는 관로의 상태를 확인할 수 없기 때문에 순간적으로 발생하는 침수에 대하여 신속하게 대처를 해야 한다. 현재 침수 피해를 신속하게 대처하기 위하여 CCTV를 활용해 침수의 발생여부를 모니터링 하고 있지만 CCTV설치 지역에 비하여 적은 인력으로 모든 CCTV를 확인하지 못하여 침수피해를 신속하게 대처하지 못하고 있는 실정이다. 본 연구에서는 침수사진 자료를 CNN(Convolutional Neural Network)기법을 이용하여 학습시켜 침수의 발생여부를 판단하는 모델을 제안하였다. 딥러닝 기법의 CNN은 이미지의 특징을 추출하여 학습하는 과정을 가지게 되는데 학습이 완료된 모델은 침수사진의 특징을 파악하여 침수가 발생하였는지에 대한 여부를 자동적으로 판단하게 된다. 본 연구결과를 CCTV관재센터 혹은 지자체와의 연계를 통하여 침수의 발생여부를 자동적으로 판단해주는 시스템이 개발된다면 신속한 침수피해 대처가 이루어 질 수 있을 것이라 판단된다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.5
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• pp.657-673
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• 2019

A monitoring method based on acoustic emission (AE) sensor has been widely used to evaluate the damage of structures in underground rock. The acoustic emission signal generated from cracking in material is analyzed as various acoustic emission parameters in time and frequency domain. To investigate from initial crack generation to final failure of rock material, it is important to understand the characteristics of acoustic emission parameters according to the stress ratio and rock strength. In this study, uniaxial compression tests were performed using very strong and weak rock specimen in order to investigate the acoustic emission parameters when the failure of specimen occurred. In the results of experimental tests, the event, root-mean-square (RMS) voltage, amplitude, and absolute energy of very strong rock specimen were larger than those of the weak rock specimen with an increase of stress ratio. In addition, the acoustic emission parameters related in frequency were more affected by specification (e.g., operation and resonant frequency) of sensors than the stress ratio or rock strength. It is expected that this study may be meaningful for evaluating the damage of underground rock when the health monitoring based on the acoustic emission technique will be performed.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.5
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• pp.675-687
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• 2019

In recent years, the needs for double deck-tunnels have increased in large cities due to the increase in traffic volume and high land compensation costs. In Korea, a network type tunnel which is smaller than general road tunnels and crosses another tunnel underground is planned. In the shield tunnel joints between the existing shield tunnel and the box-type enlargement section, a partial steel-concrete joint is proposed where the bending moment is large instead of the existing full-section steel joint. In order to analysis the enlargement section of the shield tunnel diverged section to reflect the three-dimensional effect, the two-dimensional analysis model is considered to consider the column effect and the stiffness effect of the longitudinal member. A two-dimensional analysis method is proposed to reflect the stiffness of the longitudinal member and the column effect of the longitudinal point by considering the rigidity of the longitudinal member as the elastic spring point of the connecting part in the lateral model. As a result of the analysis of the model using the longitudinal member, it was considered that the structural safety of the partial steel-concrete joint can be secured by reducing the bending moment of the joint and the box member by introducing the longitudinal member having the stiffness equal to or greater than a certain value.

• Journal of Korean Tunnelling and Underground Space Association
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• v.22 no.1
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• pp.59-76
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• 2020

As a continuous increase in demand for the transportation infrastructure in the metropolitan area, the renovation of existing metropolitan and urban railway lines for the rapid transport system requires the construction of sidetrack that can operate local and express trains simultaneously. However, the construction of sidetrack after stopping the operation of the existing subway line causes a lot of economic losses, therefore it is essential to study the tunnel enlargement scheme during the operation of the existing subway tunnel. Accordingly, in this paper, basic research on the enlargement plan of the existing subway tunnel was carried out for the renovation of the existing subway line. In order to investigate the method for the sidetrack construction, the Government Complex Gwacheon station on the Gwacheon line of subway line 4 was selected as a virtual research station. Subsequently, four construction plans including tunnel cross-sectional plan for each section were reviewed and constructability and economic feasibility were compared. Finally, the stability assessment was conducted for the selected construction plan which was considered to be relatively unstable by 3-D full numerical analysis considering the sidetrack construction process.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.6
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• pp.1161-1175
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• 2018

An unexpected event could be easily followed by a large secondary accident due to the limitation in sight of drivers in road tunnels. Therefore, a series of automated incident detection systems have been under operation, which, however, appear in very low detection rates due to very low image qualities on CCTVs in tunnels. In order to overcome that limit, deep learning based tunnel incident detection system was developed, which already showed high detection rates in November of 2017. However, since the object detection process could deal with only still images, moving direction and speed of moving vehicles could not be identified. Furthermore it was hard to detect stopping and reverse the status of moving vehicles. Therefore, apart from the object detection, an object tracking method has been introduced and combined with the detection algorithm to track the moving vehicles. Also, stopping-reverse discrimination algorithm was proposed, thereby implementing into the combined incident detection processes. Each performance on detection of stopping, reverse driving and fire incident state were evaluated with showing 100% detection rate. But the detection for 'person' object appears relatively low success rate to 78.5%. Nevertheless, it is believed that the enlarged richness of image big-data could dramatically enhance the detection capacity of the automatic incident detection system.