• Journal of Korean Tunnelling and Underground Space Association
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• v.18 no.3
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• pp.319-329
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• 2016

Underground structures such as subsea tunnel having large section should be stable against seismic loads. In general, underground structures show more stable behavior due to the limited dynamic motion and force, and considerable energy dissipation; however, severe damage was reported from recent earthquakes. Therefore, more sophisticated and analytic approach is required to investigate the seismic response of underground structure like subsea tunnel. In this study, seismic analysis of virtual Honam-Jeju subsea tunnel are performed. Consequently, stresses and forces of tunnel lining increased at fractured and/or weak rock zones. Stresses and forces of tunnel lining also increased at large section under axially deformed condition; however, decrease under transversely deformed condition.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.3
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• pp.439-448
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• 2018

Conventional Earthquake Early Warning System (EEWS) detects the propagated P-wave from epicenter which should be achieved within 5 seconds to provide seconds to minutes of warning, allowing people to prepare for protective actions. EEWS in Korea is currently capable of providing a warning within 50 seconds after the primary P-wave detection, however, it is well-known that earthquake warning systems operating around Korean National Parks (KNP) have limited capability to fully monitor earthquake events. This study, therefore, presents a strategy to quantify the potential vulnerability to earthquake hazards by superimposing the distribution of Korea Integrated Seismic System (KISS) and the discretized map of KNP. Total 22 national parks are evaluated, and the results suggest that the improvement of the on-site systems should be necessitated for Gyoengju, Gyeryongsan, Songnisan, Gayasan, and Deogyusan national parks, whereas enhancement of regional systems is required for Bukhansan national park.

• Tunnel and Underground Space
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• v.16 no.4 s.63
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• pp.288-295
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• 2006

In this study, dynamic behavior of the vehicles is analyzed, while the track is subjected to lateral vibrations due to earthquake and blasting load. A computer program(WERIA, Wheel Rail Interaction Analysis) is used, which can simulate dynamic responses of vehicles subjected to lateral vibrations. The analysis considers two types of vehicles: I.e. power cars of KTX and Busan subway train. It can also consider the interaction with sub-structures such as tracks and soil. The creep force module is considered, and the running safety of railway vehicles subjected to earthquake and blasting loading is studied. Based on the results of this study, the running safety of the vehicles can be confirmed against lateral vibration.

• Magazine of the Korean Society of Hazard Mitigation
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• v.8 no.2
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• pp.25-34
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• 2008

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.5
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• pp.385-392
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• 2014

The isolators have been generally used to reduce a seismic force. If the isolators apply to the nuclear power plants(NPPs), the durability and capacity for the structures and equipments should be ensured during the life time. In this study, the long-term behavior of isolated NPPs was analyzed for ensuring the seismic safety. The properties of isolator due to the age-related degradation were analyzed. And the seismic behavior of isolated buildings was analyzed by considering the aging of rubber bearings in different temperature environments. According to the analysis results, the natural frequency of structures was increased with time. But the maximum acceleration and maximum displacement of isolated structures have not changed significantly. Although the damaged of structure did not occurred by aging of isolators, it was presented that the spectral acceleration at the target frequency of isolated structure increased with the temperature. Therefore the isolators in the isolated buildings should be carefully designed and manufactured considering the temperature-dependancy of rubber material.

• Journal of the Earthquake Engineering Society of Korea
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• v.4 no.2
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• pp.65-72
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• 2000

콘크리트 구조물이 지진 등으로 손상을 입었을 때 그 내부 상태를 파악하는 일은 구조물의 안전성 판단에 필요한 중요 과정중 하나이다 손상도 파악에 사용되는 비파괴 검사 방법 중 레이더법은 현재 콘크리트 부재의 두께와 매립된 철근 및 공동 탐사에 적용되고 있다 레이더법은 다른 비파괴 검사 방법에서와 마찬가지로 측정된 신호의 처리와 해석에 따라 그 결과가 좌우된다 . 이논문에서는 상용 레이더 시스템에서 얻어지는 화상 데이트터를 개선하는 방법을 개발하여 철근이 매립된 콘크리트 시편에 적용하였다 실험에 사용된 기편의 크기는 1,000mm(길이)$\times$600mm (폭) $\times$140mm(두께) 이고 철근의 매립깊이는 표면으로부터 철근 중심까지 60mm 이다 레이더 실측 실험에서 철근의 수평배근 간격을 60 90, 120, 150 mm 로 변화시켜 간격탐사가능성을 시험하였다 결과적으로 상용 시스템에 비해 샹상된 판별효과를 나타냈으며 배근 간격이 90, 120, 150mm 인 시편에서 그 간격을 정확히 찾아내었다.

• The Journal of Engineering Geology
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• v.30 no.4
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• pp.617-634
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• 2020

The purpose of this study is to investigate the relationship of between earthquakes and fluctuation of water level in a groundwater well of the active-fault zone and 124 national groundwater monitoring wells in Gyeongju area. The spatial and temporal relationships between the fluctuation of water level and the earthquake were analyzed by the calculation of earthquake effectiveness (ε) and q-factor which are the function of earthquake magnitude and distance from epicenter. Two earthquake events of E1 (April 22, 2019, M 3.8) and E2 (June 11, 2019, M 2.5) show a close relationship with a post-seismic 83 cm decrease and a pre-seismic 76 cm increase in water level at the active fault zone of Dangu-ri, respectively. The spatial analysis of water level fluctuation data in National Groundwater Monitoring Networks caused by earthquake events shows a more distinct response in deep groundwater around fault zones than other area, and a greater change in deep groundwater than shallow groundwater. It's inferred that the decrease and increase in groundwater level are affected by the expansion of fractures and compression of rock mass due to seismic stress, respectively. The effective ranges of ε-value and q-factor of the monitoring well in Dangu-ri were calculated as 2.70E-10~5.60E-10 and 14.4~18.0, respectively.

• Computational Structural Engineering
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• v.8 no.1
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• pp.13-18
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• 1995

원전의 주요 구조물은 극심한 재해를 초래할 수 있는 자연현상(지진, 쓰나미 등)이 수반하는 극한하중에 견딜 수 있어야 하고 내부의 안전관련 기기의 기능과 만일의 사고(주증기나 고에너지 배관파단사고)시에도 구조적 안전성이 보장되도록 설계.시공되고 있다. 또한 운전원의 조작실수나 오판을 극복할 수 있도록 원자로 고유의 안전성과 자연법칙에 의한 정상유지를 할 수 있는 신기술이 도입되고 있다. 품질보증 계획에 의한 최선의 품질보장, 엄격한 방사선 감시와 온배수 영향의 최소화, 최신방사성 폐기물 처분기술 적용 등을 통하여 기술의존형 에너지인 원자력의 활용증대가 불가피하다고 판단된다.

• Nuclear industry
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• v.16 no.6 s.160
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• pp.4-14
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• 1996

한국형 원자로를 개량, 2001년부터 건설될 제2세대 원자로의 뒤를 이을 제3세대 원자로인 한국형 신형 원자로 CT-1300의 개념 설계가 최근 마무리되었다. CT-1300은 혁신적인 피동 설계 개념을 이용하여 안전도를 대폭 향상시킨 원자로이다. 즉 무거운 것은 아래로 내려가고 가벼운 것은 위로 올라간다는 불변의 자연법칙을 이용하여 각종 안전 장치를 설계함으로써 , 설령 지진이나 폭격 등의 원인으로 발전소에 이상이 생길지라도 안전 장치가 운전원이나 전기 장치의 도움 없이 작동할 수 있도록 한다는 것이다. 피동 설계 개념은 발전소의 안전성 향상 뿐만 아니라 경제성에도 크게 기여할 것으로 기대된다.

• Journal of the Korean Geotechnical Society
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• v.27 no.3
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• pp.41-54
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• 2011

The present study analyzes the stability of waterfront quay wall under the combined action of earthquake and tsunami. Adopting the limit equilibrium method, the stability of waterfront quay wall is checked for both the sliding and overturning. Forces due to tsunami are compared with the proposed formula and the 3-D one-field Model for immiscible TWO-Phase flows (TWOPM-3D). Variations of the stability of wall are also proposed by the parametric study including tsunami water height, horizontal seismic acceleration coefficient, internal friction angle of soil, friction angle between the wall and the soil and the pore water pressure ratio. The present study about the stability of wall is also compared with the case when earthquake and tsunami are not considered. As a result, the result of numerical analysis about the tsunami force is similar to that of proposed formula. When earthquake and tsunami are simultaneously considered, the stability of wall in passive case significantly decreases and tsunami forces in active case are affected as a resistance force on the wall and so the stability of wall increases.