• 한국지하수토양환경학회지:지하수토양환경
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• 제20권3호
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• pp.41-50
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• 2015

Hydrogeologic environment of the Mega City such as Seoul, suffers from rapid changes caused by urbanization, construction of underground subway or buildings, and contaminant loading by diverse anthropogenic activities. Understanding the present condition of groundwater environment and water budget is necessary to prevent natural and manmade disasters and to prepare for sustainable water resource management of urban environment. In this study, regional groundwater flow and water budget status of Seoul was analyzed using numerical simulation. Modeling result indicated that groundwater level distribution of Seoul generally followed the topography, but the significant decreases in groundwater level were observed around the subway network. Steady-state water balance analysis showed groundwater recharge by rainfall and leakage from the water supply network was about 550,495 m³/day. Surface water inflow and baseflow rate via Han River and major streams accounted for 799,689 m³/day and 1,103,906 m³/day, respectively. Groundwater usage was 60,945 m³/day, and the total groundwater leakage along the subway lines amounted to 114,746 m³/day. Modeling results revealed that the subway could decrease net groundwater baseflow by 40%. Our study result demonstrated that the subway system can have a significant influence on the groundwater environment of Seoul.

• Earthquakes and Structures
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• 제24권4호
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• pp.303-316
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• 2023

Rapid post-earthquake damage estimation of subway stations is particularly necessary to improve short-term crisis management and safety measures of urban subway systems after a destructive earthquake. The conventional Performance-Based Earthquake Engineering (PBEE) framework with constant earthquake occurrence rate is invalid to estimate the aftershock risk because of the time-varying rate of aftershocks and the uncertainty of mainshock-damaged state before the occurrence of aftershocks. This study presents a time-varying probabilistic seismic risk assessment framework for underground structures considering mainshock and aftershock hazards. A discrete non-omogeneous Markov process is adopted to quantify the time-varying nature of aftershock hazard and the uncertainties of structural damage states following mainshock. The time-varying seismic risk of a typical rectangular frame subway station is assessed under mainshock-only (MS) hazard and mainshock-aftershock (MSAS) hazard. The results show that the probabilities of exceeding same limit states over the service life under MSAS hazard are larger than the values under MS hazard. For the same probability of exceedance, the higher response demands are found when aftershocks are considered. As the severity of damage state for the station structure increases, the difference of the probability of exceedance increases when aftershocks are considered. PSDR=1.0% is used as the collapse prevention performance criteria for the subway station is reasonable for both the MS hazard and MSAS hazard. However, if the effect of aftershock hazard is neglected, it can significantly underestimate the response demands and the uncertainties of potential damage states for the subway station over the service life.

• Asian Journal of Atmospheric Environment
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• 제4권3호
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• pp.115-140
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• 2010

Great concerns about atmospheric aerosols are attributed to their multiple roles to atmospheric processes. For example, atmospheric aerosols influence global climate, directly by scattering or absorbing solar radiations and indirectly by serving as cloud condensation nuclei. They also have a significant impact on human health and visibility. Many of these effects depend on the size and composition of atmospheric aerosols, and thus detailed information on the physicochemical properties and the distribution of airborne particles is critical to accurately predict their impact on the Earth's climate as well as human health. A single particle analysis technique, named low-Z particle electron probe X-ray microanalysis (low-Z particle EPMA) that can determine the concentration of low-Z elements such as carbon, nitrogen and oxygen in a microscopic volume has been developed. The capability of quantitative analysis of low-Z elements in individual particle allows the characterization of especially important atmospheric particles such as sulfates, nitrates, ammonium, and carbonaceous particles. Furthermore, the diversity and the complicated heterogeneity of atmospheric particles in chemical compositions can be investigated in detail. In this review, the development and methodology of low-Z particle EPMA for the analysis of atmospheric aerosols are introduced. Also, its typical applications for the characterization of various atmospheric particles, i.e., on the chemical compositions, morphologies, the size segregated distributions, and the origins of Asian dust, urban aerosols, indoor aerosols in underground subway station, and Arctic aerosols, are illustrated.

• 한국환경보건학회지
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• 제27권2호
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• pp.1-9
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• 2001

This study was carried out to investigate the microbial characteristics of the urban air pollution in the subway stations, streets, department stores, wholesale markets, underground shopping centers, buildings, parks, houses and apartments in the Seoul and the suburbs area. Total cell count, total mold count and the presence of opportunistic pathogens(Streptococcus pneumoniae, Klebsiella pneumoniae, Aspergillus spp., Penicillium spp.) were evaluated determine the microbial air quality. Total cell count and mold count of indoor air in the houses and apartments were 2.9$\times$10$^2$-6.3$\times$10$^2$cfu/㎥ and 60-1.8$\times$10$^2$cfu/㎥, respectively, and the department stores and wholesale markets had much lower cell count than the houses and apartments. Ground level of commercial stations were 2.6 fold higher than the general subway stations, and Apergillus spp. and Penicillium spp. which could cause the bronchus and lung diseases were detected 17 sampling site out of 45. Dust were collected from the commercial facilities and houses, and total cell and mold count of the dust were 4.3$\times$10$^3$-1.7$\times$10$^{6}$ cfu/g and 2.3$\times$10$^3$-6.5 $\times$10$^4$cfu/g, respectively. Therefore the dust might be one of the main reservoir of microorganims.

• 터널과지하공간
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• 제30권2호
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• pp.149-163
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• 2020

본 연구에서는 지리정보시스템 환경에서 지하매설물 정보를 이용하여 토립자 유실을 고려한 도시 지반 함몰 취약성을 평가하였다. 지하 환경에서 물의 흐름이나 지하수위 변화에 의한 토립자 유실은 지하공동의 발생과 확장을 유도하고, 이는 지반함몰 발생에 직접적인 원인이 된다. 토립자 유실은 지하 환경에 따라 그 정도가 달라질 수 있기 때문에 본 연구에서는 지하매설물 2종(상수도 관망, 하수관로)과 지하철 선로 권역별로 지반함몰에 영향을 주는 인자를 각각 4개씩 선정하였다. 로지스틱 회귀분석 기법을 이용하여 지하매설물 및 지하철 선로 권역 별로 지반함몰 이력과 영향인자 간의 상관성을 분석하고 회귀식을 도출하였으며, 이를 토대로 3개의 지반함몰 취약성 지도를 작성하였다. 본 연구 결과는 도시 지반함몰 위험 예·경보 시스템 구축을 위한 지반함몰 고위험지역 및 지반 안전 상시 모니터링 지역 선정 근거에 대한 기초 자료를 제공할 수 있을 것으로 기대한다.

• 한국터널지하공간학회 논문집
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• 제22권1호
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• pp.59-76
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• 2020

지속적인 수도권 교통 인프라 수요의 증가에 따른 광역·도시철도 노선의 급행화를 위해서는 완행과 급행철도를 동시에 운영할 수 있도록 하는 부본선의 건설이 요구된다. 그러나 기존 지하철 노선의 운행을 중단한 후 부본선을 건설하는 것은 많은 경제적 손실을 발생시키므로 기존 지하철 터널의 운영 중 확폭 방안에 대한 연구가 필수적이다. 따라서 본 논문에서는 기존 노선 급행화에 필요한 부본선 건설을 위해 기존 지하철 터널의 운영 중 확폭 방안에 대한 기초연구를 수행하였다. 기존선 운영 중 부본선 건설방안 모색을 위해 지하철 4호선 과천선의 정부과천청사역을 부본선 건설 가상 역사로 선정하고, 4가지 방안의 구간별 단면 및 공법계획을 검토하였으며, 해당 역사에 대하여 부본선을 시공하였을 경우 시공성·경제성에 비해 상대적으로 안정성이 우려된다고 판단되는 방안을 선정하여 부본선 시공과정을 고려한 3차원 수치해석을 통한 안정성 검토를 수행하였다.

• 한국안전학회지
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• 제37권4호
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• pp.58-62
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• 2022

Metro subway construction is a field that requires a great deal of professional manpower. The aging of professionals has a negative impact on both productivity and health, owing to poor working environments, heavy lifting, underground work, and other factors. To address this issue, the government is progressively revising and enforcing health management law and regulation in the construction industry. Thus, the job stress and work ability of many professional subway construction workers, who are rapidly aging, are being analyzed to ensure their safety and improve their health. In this study, the Macpa stress index of Busan Metro Subway construction workers from Sasang to Hadan line was measured by using a Macpa measurement machine, and a work ability survey was conducted by using the questionnaire that was developed by the FIOH. The independent variables were age, years of service, job position, employment type, and occupation. While, the dependent variables were the Macpa stress index and work ability. The Kruskal-Wallis test was used because it was difficult to assume that the statistics of this study represented a normal distribution. The results showed that age, job position, and employment type affected Macpa stress index and revealed that as the age of the workers increased, their stress levels increased as well. Additionally, job position and employment type affected the work ability of the metro subway construction workers. In terms of job position, the technical engineers were under a lot of stress, and whereas the managers had the best work ability. The technical engineers were more stressed than the other workers because of a poor working environment. In terms of employment type, daily workers were under more stress and lower work ability than others.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1132-1137
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• 2010

There are execute of new laws about prevent of earthquake diaster in nation because of some increments of big earthquake occurence frequency. Now develope new composit plate by ductile fiber with strong mechanic materials, which compose of strengthening systems for the underground structures subject to forced displacements. This study is to focus to develop the retrofitting system for the cut and cuver tunnels built without earthquake type load scenario, so that it can provide the safety of existing urban subway system against earthquakes.

• 한국터널지하공간학회 논문집
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• 제5권2호
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• pp.101-113
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• 2003

현재 기존 지하구조물의 안정성에 영향을 미치는 신축구조물의 건설이 많아지므로 설계 및 시공 중 기술적으로 많은 문제점이 발생하고 있으며, 이러한 근접시공은 지하구조물의 중요도에 따라 지하구조물의 안정성과 신축구조물의 경제성이라는 두 사안이 절충 가능한 합리적인 설계 및 시공이 절실히 요구되고 있다. 지금까지의 지하구조물의 안정영역 및 지반거동에 관한 많은 연구가 이루어져 왔으나, 본 논문에서는 지하구조물의 상부에 구조물 건설에 따른 하중이 작용할 경우 지하구조물과 신축 지상구조물의 상호위치, 토피고 및 대상 지반조건이 지하구조물의 안정성에 미치는 영향 및 안정영역의 범위에 대하여 재평가하였다.

• 터널과지하공간
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• 제28권6호
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• pp.596-608
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• 2018

도시 기반시설이 노후화됨에 따라 도시 재난 발생 가능성이 증가하고 있다. 특히, 하수관로, 상수도관망, 지하철 등 노후화된 지하 시설물은 도심지 지반함몰을 유발하는 잠재적 원인이 된다. 도심지 지반함몰은 토양 침식 혹은 유실로 인해 생성된 지하 공동이 확장하여 지역적이고 갑작스런 지반 붕괴까지 이르는 현상으로 정의할 수 있다. 이는 석회암과 같은 용해성 암반에서 발생하는 싱크홀과는 구분된다. 지반 거동과 관련된 전통적인 계측 방식은 좁은 측정 범위와 각 센싱 지점에서의 계측값을 제공하기 때문에 불특정 다수 지역에서 발생할 수 있는 지반함몰 감시체계로서 한계가 있다. 따라서, 도시에 발생하는 지하 공동에 의한 지반함몰을 예방하기 위한 감시체계로서는 적절하지 않으며 지반 내 물리적 환경변화를 감시할 수 있는 새로운 상시 영역 감시 기술이 필요하다. 본 연구에서는 비방사 유도 자기장(자기공명) 기반 감시 체계의 기술적 타당성을 실험적으로 검토하였다. 공기, 물, 흙 등 매질과 공진 주파수, 임피던스 그리고 송 수신기 거리 등과 같은 환경변수에 따른 경로 손실 변화를 측정하는 방식으로 이루어졌다. 이론적으로 자기장의 전달 특성은 매질의 밀도와 독립된 것으로 알려졌으나, 실험 결과 매질의 조건에 따라 경로 손실에 의미있는 차이를 보이는 것으로 나타났다. 또한, 매질의 물리적 환경변화에 따라 경로손실보다는 반사계수가 명확한 차이를 보였으며, 입력 반사계수가 출력 반사계수에 비해 보다 판별이 용이한 것으로 나타났다.