• The Journal of Engineering Geology
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• v.10 no.3
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• pp.237-245
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• 2000

This study was for characterizing the engineering geological properties of Moryang Fault, and providing the basic data for tunnel design. Land-sat image analysis, geologic surveys, resistivity prospecting and 3-dimensional analysis for results of resistivity prospecting, core boring, mineralogical identification and chemical analysis for the bedrock, and K-Ar age dating for fault clay were carried out for the study of Moryang Fault which is located at Duckhyunri Sangbukmyun Uljinkun Ulsan metropolis. As a result of the study, it was shown that strike/dip was N20-3$0^{\circ}C$E/70-9$0^{\circ}C$NW, width of fault ranged from 20 to 60m(maximum 80m), and depth was more than 50m. K-Ar age dating results of fault clay were 5,700$\pm$1.129Ma and 1,900$\pm$0.380Ma. Hydraulic fracturing test results showed the principal stress direction similar to the strike of Moryang Fault.

• Economic and Environmental Geology
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• v.39 no.4 s.179
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• pp.451-471
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• 2006

Major projects and research topics in the field of rock mechanics are analyzed to obtain the following results: $\cdot$ Rock mechanics deals with the behavior of deformation, failure and displacement of the rock and rock mass on the basis of geological basics. Discontinuities in the rock mass are the most important parameters to control the behavior of rock mass around underground openings. $\cdot$ The objective of site investigation and testing is to determine the strength properties of the rock mass and the in situ stress regime. Specimens for laboratory and in situ tests are to be selected in order that the results of the tests give the representative properties oi the rock mass of the site in question. $\cdot$ The result of a numerical model would be better evaluated not quantitatively but qualitatively. The displacement behavior of the rock mass has to be monitored properly for the NATM (New Austrian Tunneling Method) principles. $\cdot$ The stability of rock slope is to be evaluated preferably by back analysis with strength parameters, such as cohesion and friction angle.

• Tunnel and Underground Space
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• v.19 no.2
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• pp.132-145
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• 2009

Faults in rock mass have strong influences on the behaviors of rock structure such as rock slope, tunnel and underground space. Thus, it is very important to analyse for the characteristics of fault rocks in design for tunnel. But, due to the limitation of geotechnical investigation in design stages, tunnel engineers have to carry out the face mapping and additional geological survey during tunnel excavation to find the distribution of faults and the engineering properties of faults for support and reinforcement design of tunnel. In this study, various geological survey and field tests were carried out to analyse the characteristics of the large thrust fault zone through the large sectional tunnel is constructed in mica-schist region. Also, the distribution of structural geology, the shape of thrust faults and the mechanical properties of fault rock were studied for the reasonable design of the reinforcement and support method for the highly fractured fault zone in the large-span tunnel.

• The Journal of Engineering Geology
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• v.12 no.2
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• pp.179-188
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• 2002

With improving computer penormance and advancing simulation techniques, a growing number of softwares are being developed for visualization of investigation results in geotechnical problems. It is a very important subject for geological site investigation to understand or predict if there would be any hazardous geological conclition that might cause any increase of construction costs or an extension of construction period. A 3-D (three-climensional) visualization technique may be one of the powerful tools to overcome an uncertainty problem of geologica] site investigatior. The paper describes an overview of a newly developed geotechnical 3-D interpretation system for the purpose of applying the 3-D visualization technique, GIS (geographic information system) and D/B (database) to tunnel design and construction. VR (virtual reality) and 3-D visualization techniques are applied in order to develope the 3-D model of characteristics and structures of rock mass. D/B system for all the materials related to site investigation and tunnel construction is developed using GIS technique. This system is very useful for civil engineers to make a plan of tunnel construction at the design stage and also during construction with the advantage of improving the economy and safety of tunnels.

• The Journal of Engineering Geology
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• v.27 no.1
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• pp.9-20
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• 2017

To date, several studies have been carried out to partially compare and analyze the resistivity values within the Yangsan fault zone through the electrical resistivity survey of the exposed fault zone. However, it is not easy to directly observe a large scaled fault like Yangsan fault that has been weathered, especially due to the weathering of the fault core. This study aimed to reveal the characteristics of location, geometry, the fault core zone as well as underground distribution of the associated fault damage zone, based on the results of electrical resistivity and micro-topographic surveys as well as field geology survey in the southern Yangsan fault zone (Eonyang area). The resistivity anomaly zones developed in the NNE to NE direction were confirmed by the electrical resistivity survey. According to the electrical resistivity, micro-topographic, and field geologic surveys, the Yangsan fault has been formed by three to five fault cores, fault damage zones and/or fractured zones.

• Magazine of korean Tunnelling and Underground Space Association
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• v.13 no.6
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• pp.68-80
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• 2011

해저터널은 태풍, 폭우 등과 같은 악천후에도 안정적으로 자국내 도서지역 및 인접국가간 교통 및 물류수송체계 운용을 가능하게 하는 주요 사회기반시설로서 활용되어왔다. 이러한 해저터널 프로젝트를 안전하고 경제적으로 수행하기 위해서는 해저터널의 공학적 특성을 정확하게 이해하는 것이 매우 중요하다. 이에 해저터널의 지반조사를 중심으로 전반적으로 언급하였다. 해저터널은 육상터널과는 달리 조사, 설계 및 시공단계에 있어 많은 불확실성과 위험성을 가지고 있으므로, 프로젝트의 특성에 맞는 정밀하고 정확한 조사는 해저터널의 성공여부를 좌우할 수 있다. 따라서 계획단계에서 철저한 문헌조사 연구 및 해저지형, 지질구조 등에 대한 이해를 기반으로 해저지반 조사계획을 수립 및 수행하여야 한다. 또한 해저터널의 특성상 완벽한 지반조사는 불가능하므로 광범위한 조사에도 불구하고 사전에 예상치 못한 불량한 지반조건을 마주칠 가능성이 크므로, 불확실성과 위험성을 염두에 두고 설계 및 시공에 임하여야 한다.

• Tunnel and Underground Space
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• v.29 no.4
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• pp.215-229
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• 2019

This technical note describes the current status of Finnish radioactive waste disposal project which started to construct the repository for spent nuclear waste for the first time in the world. Finland started operating nuclear power plant in 1977 and is currently operating four nuclear power plants. After detailed site surveys started in 1993, Olkiluoto was finally selected by the parliament of Finland as the site for geological disposal in 2001 followed by a construction license in 2015. If the operating license is approved by the government in the 2020s, it would be the world's first case of geological disposal. In ONKALO, a site-specific underground research facility at the site of Olkiluoto, various studies were conducted to verify the safety of the repository. Finland uses the KBS-3 disposal concept, and Korea considers a similar disposal concept because of similar rock formations. The entire process in Finland including the operation status of intermediate and low-level waste disposal, site investigation and selection stages, and the latest rock mechanics and hydrogeological studies in ONKALO are presented. Suggestions for the radioactive waste disposal in Korea is given based on the Finnish case.

• The Journal of Engineering Geology
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• v.17 no.2 s.52
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• pp.235-251
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• 2007

Baeknokdam rock mass at the crest of Halla mountain is composed of Baeknokdam trachybasalt in the eastern region and Hallasan trachyte in the western region. On-going weathering, rockfall and collapse of Baeknokdam wall rock are closely linked to the weathering of trachyte distributed in the western region of Baeknokdam, though within the restricted area of eastern region trachybasalt blocks has been naturally formed and may be rolled down neering properties have been conducted. Based on the results of these experiments variations of mineralogical-petrographical characteristics of trachyte together with chemical and physical properties with respect to the degree of weathering have been analyzed. Weathering mechanism of Baeknokdam trachyte has been delineated by investigating the environmental cause of weathering and the peculiar features of weathered rock mass.

• Journal of the Korean Geotechnical Society
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• v.22 no.2
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• pp.55-68
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• 2006

For the reliable prediction of spatial geotechnical data, a procedure to build the Geotechnical Information System (GTIS) based on geo-knowledge within the frame of GIS technology was developed by introducing a couple of new concepts of the extended area containing the study area and the additional site visit for acquiring surface geological data. To build the GTIS for Gyeongju as the case study of regional model application, intensive site investigations and pre-existing geotechnical data collections were performed and additional site visit was also carried out for acquiring surface geo-layer data in accordance with the developed procedure. Within the GTIS based on geo-knowledge for Gyeongiu area, the spatially distributed geo-layers across the extended area were predicted using the geostatistical kriging method and those for the study area were extracted. Furthermore, the spatial distribution maps for the thickess of geo-layers and the depth to bedrock were constructed for the practical use in geotechnical field. It was evaluated that the GTIS based on geo-knowledge developed in this study is superior to the conventional geotechnical GIS in terms of both the standard deviation and the geological expert judgment.

• The Journal of Engineering Geology
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• v.26 no.2
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• pp.277-290
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• 2016

Deep geological cross-sectional data is generally not common nor easy to construct, because it is expensive and requires a great deal of time. As a result, geological interpretations at depth are limited. Many scientists attempt to construct geological cross-sections at depth using geological surface data and geophysical data. In this paper, we suggest a method for constructing cross-sections from limited geological surface data in a target area. The reason for this study is to construct and interpret geological cros-sections at depth to evaluate heat flow anomaly along the Yangsan fault. The Yangsan Fault passes through the south-eastern part of the Korean Peninsula. The cross-section is constructed from Sangbukmyeon to Unchonmyeon passing perpendicularly through the Yangsan Fault System trending NW-SE direction. The geological cross-section is constructed using the following data: (1) Lithologic distributions and main structural elements. (2) Extensity of sedimentary rock and igneous rock, from field mapping. (3) Fault dimension calculated based on geometry of exposed surface rupture, and (4) Seismic and core logging data. The Yangsan Fault System is composed of the Jain fault, Milyang fault, Moryang fault, Yangsan fault, Dongnae fault, and Ingwang fault which strike NNE-SSW. According to field observation, the western section of the Yangsan fault bounded by igneous rocks and in the eastern section sedimentary rocks are dominant. Using surface fault length we infer that the Yangsan Fault System has developed to a depth of kilometers beneath the surface. According to seismic data, sedimentary rocks that are adjacent to the Yangsan fault are thin and getting thicker towards the east of the section. In this study we also suggest a new method to recognize faults using core loggings. This analysis could be used to estimate fault locations at different scales.