• The Journal of the Convergence on Culture Technology
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• v.8 no.3
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• pp.551-557
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• 2022

Geotechnical risk factors encountered in intermediate-depth underground tunnel construction are diverse, and the types and standards of risk factors are different according to the depth and regional geological characteristics of Korea. In order to understand the effects of geological characteristics and geologic structure on safety, which show various porous characteristics of urban underground complex ground, the risk factors of intermediate-depth rock mass in Korea were analyzed based on domestic and foreign cases. As a result of the study, seven categories affecting the stability of the intermediate-depth tunneling, namely, geologic structure, rock characteristics, hydrogeology, overburden, high stress, ground characteristics and artificial structures, and about 22 risk factors were derived. We present the risk criteria and interval values for risk evaluation of faults, folds, dikes, and rocks that have the greatest influence among risk factors. Criteria and interval values for other risk factors are under study.

• Proceedings of the KSEEG Conference
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• 1999.04a
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• pp.113-115
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• 1999

• Proceedings of the KSEEG Conference
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• 1999.04a
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• pp.181-183
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• 1999

• Proceedings of the KSEEG Conference
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• 2007.04a
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• pp.520-522
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• 2007

• Proceedings of the KSEG Conference
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• 2003.04a
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• pp.49-54
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• 2003

• 한국석유지질학회:학술대회논문집
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• autumn
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• pp.59-59
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• 2000

• 한국석유지질학회:학술대회논문집
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• autumn
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• pp.21-21
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• 2000

• Economic and Environmental Geology
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• v.52 no.6
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• pp.541-554
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• 2019

The Taebaeksan Zone of the Okcheon Belt is a prominent fold-thrust belt, preserving evidence for overlapped polyphase and diachronous orogenic events during crustal evolution of the Korean Peninsula. The Pyeongchang-Jeongseon area of the northwestern Taebaeksan Zone is fault-bounded on the western Jucheon and southern Yeongwol areas, showing lateral variations in stratigraphy and structural geometries. For better understanding these geological characteristics of the northwestern Taebaeksan Zone, we have studied the structural geometry of the Pyeongchang-Jeongseon area. For this, we have firstly carried out the SHRIMP U-Pb age analysis of the age-unknown sedimentary rock to clarify stratigraphy for structural interpretation. The results show the late Carboniferous to middle Permian dates, indicating that it is correlated to the Upper Paleozoic Pyeongan Supergroup. In addition to this, we interpreted the geometric relationships between structural elements from the detailed field investigation of the study area. The major structure of the northwestern Taebaeksan Zone is the regional-scale Jeongseon Great syncline, having NE-trending hinge with second-order folds such as the Jidongri and Imhari anticlines and the Nambyeongsan syncline. Based on the stereographic and down-plunge projections of the structureal elements, the structural geometry of the Jeongseon Great syncline can be interpreted as a synformal culmination, plunging slightly to the south at its southern area, and north at the northern area. The different map patterns of the northern and southern parts of the study area should be resulted in different erosion levels caused by the plunging hinges. Considering the Jeongseon Great syncline is the major structure that constrains the distribution of the Paleozoic strata of the Pyeongchang and Jeongseon areas, the symmetric repetition of the lower Paleozoic Joseon Supergroup in both limbs should be re-examined by structural mapping of the Hangmae and Hoedongri formations in the Pyeongchang and Jeongseon areas.

• Economic and Environmental Geology
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• v.57 no.1
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• pp.41-50
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• 2024

This study reports the structural geometry and folding mechanism of a regional-scale overturned fold in the Daecheong Island, central-western part of the Korean Peninsula. Based on low-hemisphere stereographic and down-plunge projections using data from a detailed field survey, we classify the regional-scale fold as an open overturned fold shallowly plunging toward NE. The asymmetric and symmetric parasitic folds in the limb and hinge zones indicate layer-parallel shortening prior to flexural-flow folding. Fold dating must be required to decipher the orogenic process causing the regional-scale overturned fold in the Daecheong Island.

• The Journal of Engineering Geology
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• v.27 no.4
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• pp.367-376
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• 2017

Recently, tunneling under the seabed is becoming increasingly common in many countries. In Korea, there are proposals to tunnel from the mainland to Jeju Island. Safe construction requires geologic structures such as faults to be characterized during the design and construction phase; however, unlike on land, such structures are difficult to survey seabed. This study aims to develop an algorithm that uses geostatistics to automatically derive large-scale geological structures on the seabed. The most important considerations in this method are the optimal size of the moving window, the optimal type of spatial statistics, and determination of the optimal percentile standard. Finally, the optimal analysis algorithm was developed using the R program, which comprehensibly presents variations in spatial statistics. The program allows the type and percentile standard of spatial statistics to be specified by the user, thus enabling an analysis of the geological structure according to variations in spatial statistics. The geotechnical defense-training algorithm shows that a large, linear geological lineament is best visualized using a $3{\times}3$ moving window and a 10% upper standard based on the moving variance value and fractile. In particular, setting the fractile criterion to the upper 0.5% almost entirely eliminates the error values from the contour image.