• Geomechanics and Engineering
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• v.22 no.4
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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.

• Journal of Korean Society for Geospatial Information Science
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• v.17 no.2
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• pp.19-26
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• 2009

The Ministry of Land, Transport and Maritime Affairs(MLTM) project for the DB construction of national geotechnical information was automatically computerized the geotechnical investigation results on the construction site in 2007. So 'the rule for computerizing of geotechnical investigation results and its application' were promoted the establishment and applicable project. It was promoted in earnest that all organization and affiliation of MLTM, local governments included the project because of stabilization of the law from 2008. We have analyzed a application-ratio of geotechnical information about users of geotechnical information system and distribution data and established a plan of applying enhancement for the DB construction and DB utilization in 2008. In this paper, we propose the result for application-ratio analysis and application plan through the application-case study of national geotechnical information DB. In the application-ratio analysis, the analysis in the field shows the most high as 39% in construction planning and preliminary investigation, the analysis in the effect of capabilities shows the most high as 25% in the increased efficiency of business. Also the analysis in the field of application shows the most high as 95% a application-ratio of geotechnical information in architecture and civil.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.1024-1029
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• 2010

The conventional factor of safety as used in geotechnical engineering does not reflect the degree of uncertainty of the relevant parameters. Then in the geotechnical engineering, there have been efforts to reflect the uncertainties of the geotechnical properties through probabilistic analysis. In this study, a practical method for calculation the second moment reliability index using the optimization tool of a spreadsheet software is introduced. And this methodology was proposed by Low, B. K.(1996). The method is based on the perspective of an ellipsoid that just touches the failure surface in the original space of the variables. The method is applied to vertical drains(PVD) and compared with th result of Monte Carlo Simulation method.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.669-680
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• 2005

It is very difficult to determine the failure block scale in great rock slopes. Especially, postulating entire slope domain as a failure block without attention to discontinuity trace lenth makes very confuse and difficult to design rock slopes. In this paper, we estimate realistic failure block scale using joint system simulation method and introduce the application procedures on rock slope analysis. Besides, presenting how joint characteristics measurement and statistical analysis results are applicated to slope stability analysis design flow.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.719-724
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• 2005

It conducted an analysis and the research against kinetic energy distribution, velocity and bounce height according to rockfall characteristics using rockfall simulation program in cut-slope. This study considered kinetic energy and bounce height of rockfall for efficient establishment of rockfall protection fencefence that is countermeasure in cut-slope.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.1139-1146
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• 2009

Collapse of cut slope includes many uncertainties in view of the reason and time. So, in the past, risky cut slopes have been dealt after they've been collapsed through post-management measures. But recently, advanced disaster prevention system is required, and as a part of that RTMS(Real-Time Monitoring System) was developed. In this study, stability of risky cut slope was evaluated by site investigation. To grasp deformation behavior characteristics of slope, numerical analysis based on FEM was performed and using results of that, specific standards for installation of Real-Time Monitoring System were suggested.

• Proceedings of the Korean Geotechical Society Conference
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• 1997.03a
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• pp.133-146
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• 1997

• Proceedings of the KSR Conference
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• 2003.05a
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• pp.326-330
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• 2003

The purpose of this study was to develop railroad geotechnical management system using Web GIS and the DB used in system included railroad informations and digital maps. Digital maps are primarily based on a topographical map(NGIS, 1:5000) and by adding digital maps(KRRI, 1:5000) and their spatial database system to NGI code layer, the management system was developed. The system was connected to geotechnical database already developed. The system was able to separate three parts which were layer choice, geotechnical information view and geotechnical analysis and it was possible to save geotechnical and spatial informations using ZEUS DB simultaneously. ZEUS/X was used for usefulness of GIS operation and by offering GUI, user interface for facility was achieved. Geotechnical and spatial informations in this system will provide basic data for plans, design and construction of railway lines in practical use.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.593-600
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• 2000

Most of ground investigations can be grasped geological distribution which like rock name, geological structure, soil condition, underwater condition, land slide, ground cave-in, ground collapse by geological survey. But geological survey is limited to part region geological structure, not wide region. Therefore, Image Processing Method must need to grasp wide region geological structure. The object of this research is presented analysis data of geotechnical engineering in first step investigation.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.1301-1306
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• 2009

Recently, urban excavations are one of most frequent geotechnical work according to construction of a high rise building and subway. These kind of excavation affect to a adjacent ground or structure and it can trigger various severe accidents. Generally, the ground is closer to the excavation site, the deformation become larger. In this study, special ground settlement case due to adjacent ground excavation is presented and a cause of deformation is examined by various geotechnical exploration, lab-testing and numerical analysis.