• 한국측량학회지
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• 제40권5호
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• pp.413-419
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• 2022

지하공간의 개발이 활발해짐에 따라 최근에는 지하와 관련된 안전사고가 자주발생하고 있다. 이와 관련하여 국토교통부에서는 『지하안전관리에 관한 특별법』(2018.01.01. 시행, 이하 지하안전법)을 시행하고 있다. 지하안전법의 핵심이 되는 내용 중에는 현재 우리나라에서 지하공간에 존재하는 지하시설물, 지하구조물, 지반의 지하정보를 3차원으로 가시화 할 수 있도록 지하공간통합지도를 구축하고 이를 활용하는 것을 포함하고 있다. 본 연구는 지하공간통합지도 중 3차원의 지하구조물 데이터를 대상으로 3차원 모델 생성 후 이를 빠르게 검수할 수 있는 프로그램을 개발하는 것을 목적으로 한다. 이를 위하여 우선 3차원 지하구조물 데이터를 생성하고 자동 검수하는 기술에 대하여 국내·외 현황을 조사하였다. 핵심이 되는 연구내용으로는 지하공간통합지도를 구축할 때 3차원 지하구조물의 검수기준에 따라 자동으로 3차원 모델 품질을 검수하는 프로그램을 개발하였다. 본 연구를 통하여 현재 수작업 방식으로 진행하고 있는 3차원 모델 검수과정을 98% 이상 자동화함으로써 지하공간통합지도 지하구조물의 3차원 모델의 품질향상을 도모할 수 있을 것으로 기대된다.

• 한국화재소방학회논문지
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• 제30권2호
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• pp.81-86
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• 2016

최근 국내 도심지 도로는 빈번한 교통정체가 발생하고 있다. 도심지 교통정체를 해소하기 위한 방안으로 국내에서는 대심도 복층터널에 대한 계획이 이루어지고 있다. 국내에서 계획되는 대심도 복층터널은 소형차 전용으로 계획되며 네트워크형의 구조를 가지고 있어 차량의 출입이 지하공간에서 이루어지고 있다. 이러한 네트워크형 대심도 복층터널은 터널의 단면 및 높이가 일반도로터널 보다 작고 차량의 출입으로 인한 교통풍의 작용으로 화재연기가 터널 승객의 대피보다 빠르게 전파되어 인명피해 발생이 예상된다. 따라서 본 연구에서는 국내 네트워크형 대심도 복층터널에 화재시 화재연기 확산지연을 방지하고자 화재연기 확산지연 장치 작동시 터널 차단면적에 터널 내 작용하는 유입풍의 저감효과를 분석하였으며, 분석결과 터널 차단면적이 50% 이상일 경우 터널 내 작용하는 풍속을 약 21% 저감시키는 효과가 나타났으며, 면적이 50% 이상일 경우 화재 연기의 확산속도를 약 21% 저감시켜 안전한 대피에 도움이 될 것이라 판단된다.

• 한국지반환경공학회 논문집
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• 제25권1호
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• pp.5-11
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• 2024

지반함몰은 인구 밀집도가 높은 도심지에서 주로 발생함으로, 발생 원인을 명확히 파악하여 사전에 대비할 필요가 있다. 지반함몰의 주요 발생원인은 지하매설관의 손상으로 인한 지반 내 공동 생성으로 보고되어 있으나, 지반함몰 발생을 예측하여 대비하기 위한 지하매설관의 속성정보 및 영향인자가 올바르게 구축되어 있지 않은 실정이다. 따라서 본 연구에서는 지하매설물 속성정보 중 지반함몰 발생과 유의미한 상관성을 나타내는 인자를 선정하고, 로지스틱 회귀분석을 통해 회귀식을 제안하였다. 이를 위해, 대상지역의 지하매설물 및 지반함몰 이력정보의 데이터를 수집하였고, 대상지역을 QGIS를 활용하여 100m×100m 크기의 Gird로 구분하였다. Gird 내부에 포함되어 있는 지하매설물 속성정보와 지반함몰 이력정보를 추출하여 전처리를 수행하고 데이터셋을 구축하여 상관분석을 수행하였다. 그 결과, 하수관과 통신관의 매설년도와 통신관, 열배관, 가스관의 평균심도를 제외한 인자가 지반함몰과 유의미한 상관성을 보이는 것으로 나타났다. 또한, 로지스틱 회귀분석을 통해 대상지역의 지반함몰 발생 여부 회귀식을 제안하였다.

• Transactions on Control, Automation and Systems Engineering
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• 제2권1호
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• pp.69-75
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• 2000

The aim of the work described in this paper is to develop a complex underground acoustic system which detects and localizes the origin of an underground hammering sound using an array of hydrophones located about 100m underground. Three different methods for the sound localization will be presented, a time-delay method, a power-attenuation method and a hybrid method. In the time-delay method, the cross correlation of the signals received from the array of sensors is used to calculate the time delays between those signals. In the power-attenuation method, the powers of the received signals provide a measure of the distances of the source from the sensors. In the hybrid method, both informations of time-delays and power-ratios are coupled together to produce better performance of position estimation. A new acoustic imaging technique has been developed for improving the hybrid method. This new acoustic imaging method shows the multi-dimensional distribution of the normalized cost function, so as to indicate the trend of the minimizing direction toward the source location. For each method the sound localization is carried out in three dimensions underground. The distance between the true and estimated origins of the source is 28m for a search area of radius 250m.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 A
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• pp.558-560
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• 2003

The effects of surge arresters for protection of transmission systems against direct lightning strokes have already been investigated using the digital simulation program EMTP. Distribution lines are spanned on a much large area as compared to transmission lines, and therefore, are more often susceptible to lightning strokes. This paper analyzes the overvoltages on underground cable system against direct lightning strokes to the overhead ground wire using the digital simulation. The effects of lightning protection methods, such as lowering the grounding resistance and installing the surge arrester, for preventing overvoltages on underground cable system caused by direct lightning strokes to the overhead ground wire is investigated. Several schemes have been proposed to protect underground cables. This paper summarizes the main results of a study aimed at analysis of lightning overvoltages in variety underground feeders protected by metal-oxide arresters. This study will provide insulation coordination methods for reasonable system design in 22.9kV underground cable system.

• 센서학회지
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• 제24권5호
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• pp.306-310
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• 2015

IoT(Internet of Things) based underground risk assessment system surrounding water pipeline enables an advanced monitoring and prediction for unexpected underground hazards such as abrupt road-side subsidence and urban sinkholes due to a leak in water pipeline. For the development of successful assessment technology, the PSU(Water Pipeline Safety Unit) which detects the leakage and movement of water pipes. Then, the IoT-based underground risk assessment system surrounding water pipeline will be proposed. The system consists of early detection tools for underground events and correspondence services, by analyzing leakage and movement data collected from PSU. These methods must be continuous and reliable, and cover certain block area ranging a few kilometers, for properly applying to regional water supply changes.

• Earthquakes and Structures
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• 제22권3호
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• pp.277-287
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• 2022

The ancient underground cities are a collection of self-supporting spaces that have been manually excavated in the soil or rock in the past. Because these structures have a very high cultural value due to their age, the study of their stability under the influence of natural hazards, such as earthquakes, is very important. In this research, while introducing the underground city of Ouyi Nushabad located in the center of Iran as one of the largest man-made underground cities of the old world, the analysis of dynamic stability is performed. For this purpose, the dynamic stress-displacement analysis has been performed through numerical modeling using the finite element software PLAXIS. At this stage, by simulating the Khorgo earthquake as one of the large-scale earthquakes that occurred in Iran, with a magnitude of 6.9 on the Richter scale, dynamic analysis by time history method has been performed on three selected sections of underground spaces. This study shows that the maximum amount of horizontal and vertical dynamic displacement is 12.9 cm and 17.7 cm, respectively, which was obtained in section 2. The comparison of the results shows that by increasing the cross-sectional area of the excavation, especially the distance between the roof and the floor, in addition to increasing the amount of horizontal and vertical dynamic displacement, the obtained maximum acceleration is intensified compared to the mapping acceleration applied to the model floor. Therefore, preventive actions should be taken to stabilize the excavations in order to prevent damage caused by a possible earthquake.

• Geomechanics and Engineering
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• 제32권4호
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• pp.411-426
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• 2023

Soft clay is widely distributed in the southeast coastal areas of China. Many large underground structures, such as subway stations and underground pipe corridors, are shallow buried in the soft clay foundation, so the dynamic characteristics of the soft clay must be considered to the seismic design of underground structures. In this paper, the dynamic characteristics of saturated soft clay in Shanghai under the bidirectional excitation for earthquake loading are studied by dynamic triaxial tests, comparing the backbone curve and hysteretic curve of the saturated soft clay under different confining pressures with those under different vibration frequencies. Considering the coupling effects of the confining pressure and the vibration frequency, a fitting model of the maximum dynamic shear modulus was proposed by the multiple linear regression method. The M-D model was used to fit the variations of the dynamic shear modulus ratio with the shear strain. Based on the Chen model and the Park model, the effects of the consolidation confining pressure and the vibration frequency on the damping ratio were studied. The results can provide a reference to the earthquake prevention and disaster reduction in soft clay area.

• 국제학술발표논문집
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• The 5th International Conference on Construction Engineering and Project Management
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• pp.367-374
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• 2013

Underground infrastructure systems provide essential public services and goods through buried structures including water and sewer, gas and petroleum, power and communication pipelines. The majority of existing underground infrastructure systems was installed in green field areas prior to development of complex urban built environments. Currently, there is a global trend to escalate major demand for underground infrastructure system renewal and new installation while minimizing disruption and maintaining functions of existing superstructures. Therefore, Engineers and utility owners are rigorously seeking technologies that minimize environmental, social, and economic impact during the renewal and installation process. Trenchless technologies have proven to be socially less disruptive, more environmentally friendly, energy conservative and economically viable alternative methods. All of those benefits are adequate to enhance overall sustainability. This paper describes effective sustainable solutions using trenchless technologies. Sustainability is assessed by a comparison between conventional open cut and trenchless technology methods. Sustainability analysis is based on a broad perspective combining the three main aspects of sustainability: economic; environmental; and social. Economic includes construction cost, benefit, and social cost analysis. Environmental includes emission estimation and environmental quality impact study. Social includes various social impacts on an urban area. This paper summarizes sustainable trenchless technology solutions and presents a sustainable construction method selection process in a proposed framework to be used in urban underground infrastructure capital improvement projects.

• 한국대기환경학회지
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• 제14권3호
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• pp.163-176
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• 1998

In this study, airborne particle samples were obtained to determine the concentrations of particulate air pollutants in indoor and outdoor air of public facilities in Taegu area. Total of 12 public facilities, regulated by the Public Sanitary Law, were selected as sampling sites, which include three underground arcades, one railway and two bus terminals, three general hospitals, and three department stores. In each place, sampling was carried out seasonally during the period of October 1994 to July 1995, and four samples per each site per season were collected both indoors and outdoors simultaneously. After determination of suspended particulate matter (SPM) mass concentrations, the particle samples were divided into two parts for subsequent chemical analysis: one for the analysis of trace elements and the other for water soluble ions. Seasonal levels of SPM appeared to be the highest in spring and the lowest in summer both indoors and outdoors, while locational variations of highest in statioyterminals, and lowest in department stores . SPM concentrations indoors and outdoors did not show any significant differences each other in most places . However, there were significant correlations between indoor and outdoor levels of SPM and other chemical species . These results indicates that indoor SPM levels are likely to be significantly affected by outdoor sources in many places. The most significant source of SPM was estimated to be the resuspension of soil/road dust both indoors and outdoors . The concentrations of toxic heavy metals (Pb, Cd, Cr, Cu) in underground arcades appeared to be very much lower than the established air quality guidelines for underground environments. In addition, it is likely that micro-environmental parameters such as temperature, humidity, and air velocity, play a less significant role than outdoor air quality as a factor affecting the levels of particulate pollutants in indoor environments of public facilities in Taegu area.