• Journal of Korean Society for Geospatial Information Science
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• v.15 no.2 s.40
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• pp.67-75
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• 2007

There are a number of risks in constructing tunnel-structures. Therefore, the precise and rapid observation about inside deformation of the tunnel is required to prevent these risks from occurring and to secure safety. But currently, the real situation is that the crown settlement, cavity deformation and ground surface settlement rely upon the universal mensuration which uses total station or various kinds of measuring instruments. Recently, according to improvement and progress of measuring technology, three-dimensional laser scanning is used as the method to provide data for maintaining structures. It solves the reliability problem of measuring method for the transformational volume of existing structures, provides data that enables to judge visually by three-dimensioning the shape change of structures and makes it possible to deliberate speedy countermeasure. And it can also be efficiently used in the structure maintenance and field measurement.

• Journal of the Korean Institute of Gas
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• v.7 no.1 s.18
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• pp.33-40
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• 2003

In this work, a novel approach was introduced to assess cost of loss resulting from risk as well as to help deciding inspection period through quantifying risk. In order to quantifying risk of city gas pipeline, frequency and consequence analysis were required. The main causes of city gas accident were analyzed to be digging, external corrosion, ground movement, and equipment failure. Tools to evaluate frequency of each cause was also suggested. Among city gas accidents, fire damage is the dominant one and mainly discussed; fatality, burning injury, and damage to building were estimated using the consequence model suggested. By combining frequency and consequence analysis, evaluating cost of risk management together with calculating example. This work could be applicable for city gas companies to plan how to manage risk most effectively.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.11a
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• pp.165-172
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• 2008

Leakage incidents due to the fault of hazmat tank foundations are likely to cause the tremendous fire disaster in the national industry cluster area. The proper design and construction of tank foundation should be required to prevent the tank fire. In the study, the types of typical tank foundations were classified and modeling the individual tank type for 3D FEM analysis was performed to suggest the guideline for the design and construction of tank foundations. Matters to be attended of the foundation design and construction are reviewed through the comparison assessment of the numerical analysis results of the foundation types.

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2002.10a
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• pp.31-42
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• 2002

최근 지하철 터널은 사용자 편의성, 도심지 접근성 및 원활한 교통처리 등을 고려하여 지반조건이 불리한 상황에서도 터널로 계획되는 경우가 많아지고 있다 따라서 시공중의 터널안정성확보, 굴착에 따른 인접구조물의 침하영향, 발파진동영향 등을 종합적으로 고려한 지보패턴 및 보조·보강공법의 결정이 매우 중요하나 정량적인 판단기준의 부재로 인하여 주로 경험적인 설계에 의존하는 경우가 많다. 본 연구에서는 도심지 지하철 터널의 복합적인 거동특성을 고려하기 위하여 여러 가지 예상위험요소의 정량화 방안을 제안하고, 다변량 통계분석기법을 활용하여 여러 가지 위험 요소들의 특성을 함축적으로 나타내는 소수의 총합적인 지표(안정성인자, 환경성인자)로 대표화 할 수 있음을 검증하였다. 안정성 인자 및 환경성 인자를 이용한 서울시 지하철 00공구 설계사례를 통해 정량화지표(Multiple Index)의 터널설계에의 적용성을 평가하고 이의 설계시 활용방안을 제안하고자 하였다.

• Journal of the Korean Institute of Gas
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• v.7 no.2 s.19
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• pp.14-21
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• 2003

Frequency analysis of city gas pipeline was studied and then the method to give frequencies of failure by the third-party digging, corrosion, ground movement, and equipment failure which were known to be the major cause of risk of city gas pipeline. The failure by the third-party digging was analyzed by fault tree analysis and the failure by corrosion was analyzed by applying equation calculating remaining strength with time. The failure by ground movement was evaluated by applying modified model which was induced through weighing factors with basic failure rate model. The failure rate of equipment was calculated with both generic and specific data

• Geophysics and Geophysical Exploration
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• v.11 no.4
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• pp.368-372
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• 2008

This study evaluates the usefulness and capability of surface electrical resistivity technique for identifying the weak zones or subsurface cavities in karst area with limestone formation. Weak zones or cavities near surface can be potentially dangerous and several problems are associated with collapse of roads or buildings accompanied by subsidence phenomena. In this paper, both two and three dimensional resistivity investigation were conducted to investigate subsidence along a road in Yongweol-ri, Muan-gun, South Korea. The results of the resistivity survey using dipole-dipole array provide a clear view of the weathered regolith, the distribution of weak zones or cavities and bedrock. Several low resistivity areas were identified and subsequent drilling led to the discovery of several weak zone or clay-filled underground cavities. The drilling results show excellent correlation with the resistivity images. It is illustrated, the ability of electrical technique to produce high resolution images of subsurface, which are useful for subsidence assessment. Also the results of this study have demonstrated that two and three dimensional electrical resistivity surveys are useful for delineating the subsidence area. Based on resistivity imaging, the map of hazardous zone has been developed.

• Journal of the Korean GEO-environmental Society
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• v.23 no.4
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• pp.5-10
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• 2022

Recently, ground subsidence has been continuously occurring in downtown areas, threatening the safety of citizens. Various underground facilities such as water and sewage pipelines and communication pipelines are buried under the road. It is reported that the cause of ground subsidence is the deterioration of various facilities and the reckless development of the underground. In particular, it is known that the biggest cause of ground subsidence is the aging of sewage pipelines. As an existing study related to this, several representative factors of sewage pipelines were selected and a study to predict the risk of ground subsidence through statistical analysis has been conducted. In this study, a data SET was constructed using the characteristics of OO city's sewage pipe characteristics and ground subsidence data, The data set constructed from the characteristics of the sewage pipe of OO city and the location of the ground subsidence was used. The goal of this study was to present a classification model for the occurrence of ground subsidence according to the characteristics of sewage pipes through machine learning. In addition, the importance of each sewage pipe characteristic affecting the ground subsidence was calculated.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.10-17
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• 2020

Recently, the liquefaction phenomenon was first discovered in Korea due to a magnitude 5.4 earthquake that occurred in Pohang, Gyeonsangbuk-do. When liquefaction occurs, some of the water and sand are ejected to the ground, producing a space, which leads to various dangerous situations, such as ground subsidence, building collapse, and sinkhole generation. Recently, the necessity of producing a liquefaction risk map in Korea has increased to grasp potential liquefaction areas in advance. Therefore, this study examined the drilling information from the national geotechnical information DB center at the Ministry of Land, Infrastructure, and Transport to produce a liquefaction risk map, and developed a module to implement functions for basic data modeling and 3D analysis based on drilling information database extraction and information. Through this study, effective interlocking technology of the integrated database of national land information was obtained, and three-dimensional information was generated for each stage of liquefaction risk analysis, such as soil resistance value and a liquefaction risk map. In the future, the technology developed in this study can be used as a comprehensive decision support technology for establishing a foundation for building 3D liquefaction information and for establishing a response system of liquefaction.

• The Journal of Engineering Geology
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• v.31 no.2
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• pp.135-148
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• 2021

Ground subsidence risk ratings obtained from the site investigation during pre-excavation stages could be changed depending on the parameters revealed during construction activities. A method of correcting the pre-excavation ground subsidence risk ratings based on the site conditions observed in the field is suggested in this study. The elevation of groundwater table during the excavation may be different from the predicted value depending on the application of waterproofing methods and construction conditions. The drastic drawdown of groundwater table during the excavation could cause ground subsidence due to soil volume decrease related to consolidation or compression of the ground, whereas the rising of groundwater table caused by the intense rainfall may result in a high potential for ground subsidence due to heaving or boiling of the excavation bottom. Excessive displacements of retaining walls or ground settlements may cause ground subsidence, which also results in a high risk of ground subsidence caused by the destruction of buried pipelines. Reevaluation of ground subsidence risk ratings is suggested considering the fluctuation of groundwater table, condition of groundwater leakage, measured ground displacements, and soil types. Finally, the ground subsidence risk rating system is improved for better evaluation by using 12 factors in 5 categories.

• Electronics and Telecommunications Trends
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• v.30 no.5
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• pp.28-38
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• 2015

최근 빈번히 발생하고 있는 도심지 내 지반침하의 주된 원인은 지하공간의 난개발, 상하수도 시설의 노후화, 이로 인한 급격한 지하 수위의 변화에 기인한다고 알려져 있으며 이에 대한 실시간 모니터링 및 종합적인 상관성 분석을 통한 사고예방이 시급한 실정이다. 지하공간의 특수성으로 인해 광역 지하공간 정보를 실시간으로 수집하여 모니터링할 수 있는 기술이 부재한 점과 이로 인한 지하공간의 위험도 분석과 과학적 재난대응 시스템 구축에 어려움이 존재한다. 본고에서는 도시 지하공간 내 지하매설물(상하수도)의 상태와 지하공간상황(도시철도구조물, 지하수, 지반변형)을 실시간으로 모니터링하기 위한 도메인별 기술개발 동향에 대해서 정리하고, 수집된 정보의 종합적 분석을 통한 지하공간의 이상 징후를 사전감지, 예측, 대응하기 위해 도전하고 있는 기술적 이슈들을 살펴보고자 한다.