• 한국지구물리탐사학회:학술대회논문집
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• 2006.06a
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• pp.117-122
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• 2006

In the geophysical monitoring to understand the change of subsurface material properties with time, the time-invariant static subsurface model is commonly adopted to reconstruct a time-lapse image. This assumption of static model, however, can be invalid particularly when fluid migrates very quickly in highly permeable medium in the brine injection experiment. In such case, the resultant subsurface images may be severely distorted. In order to alleviate this problem, we develop a new least-squares inversion algorithm under the assumption that the subsurface model will change continuously in time. Instead of sampling a time-space model into numerous space models with a regular time interval, a few reference models in space domain at different times pre-selected are used to describe the subsurface structure continuously changing in time; the material property at a certain space coordinate are assumed to change linearly in time. Consequently, finding a space-time model can be simplified into obtaining several reference space models. In order to stabilize iterative inversion and to calculate meaningful subsurface images varying with time, the regularization along time axis is introduced assuming that the subsurface model will not change significantly during the data acquisition. The performance of the proposed algorithm is demonstrated by the numerical experiments using the synthetic data of crosshole dc resistivity tomography.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.11a
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• pp.663-666
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• 2005

공간정보의 처리에는 방대한 양의 자료가 분석되어야 하므로 강력한 컴퓨터 하드웨어와 소프트웨어의 성능이 뒷받침 되지 못했던 80/90년대와 달리 최근에 비약적인 발전을 가져온 분야중의 하나이다. 공간자료구조는 지리정보시스템(GIS)의 핵심엔진으로서 이를 활용한 공간정보의 분석과 처리는 수많은 응용을 갖고 있으며 파생되는 응용분야가 날로 증가하고 있는 추세에 있다. 그러나 대부분의 지리정보는 지상에 대한 것으로서, 지하정보에 대한 연구는 지하정보의 비가시적인 특성상 현재 초기단계라고 할 수 있다. 본 논문은 탄성파를 이용하여 얻어진 지하 지층구조 정보를 분석하여 지층구조를 파악하고, 공간자료구조를 활용하여 지하 단층대를 분석하고 검색하는 시스템 개발 방법을 제안하고 이와 관련된 사항을 기술하였다. 지하 단층대의 확인 작업은 다양한 지상/지하 구조물의 안정성에 중요한 역할을 하는 자료가 된다. 공간자료구조를 활용하여 지하지층을 인식하는 시스템의 개발은 지질 전문가의 해석을 위한 전처리 시스템으로서 중요한 역할을 할 것이다.

• The Journal of Engineering Geology
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• v.1 no.1
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• pp.109-120
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• 1991

Applications of microtremor to geological engineering are widely reviewed and observed microtremors are processed to show evidences of close relationship between the predominant periods of microtremor and underground structure. The ground vibrates continuously at all times and the elastic vibration is called microtremor (0.5-20Hz) or microseisms (0.01-0.1Hz) according to their frequency range. The vibration is believed to have propagative nature like those of the dispersive surface waves or multireflected shear waves. Microtremors were recorded at selected thress places of which subsoil structures are well distinguished in the Kyongsang Sedimentary Basin. It is found that the underground structures estimated from microtremor analysis coincide well with the known structures. The microtremor analysis of the long period range can be an inexpensive and effective tool in geological engineering for the evaluation of the underground structure, site-specific reponse spectrum, and seismic microzonations.

• Proceedings of the Korea Information Processing Society Conference
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• 2006.11a
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• pp.625-628
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• 2006

공간정보의 처리는 방대한 양의 자료처리가 필수적이므로 이를 지원할 수 있는 하드웨어와 소프트웨어의 발전과 함께 최근에 비약적인 발전을 가져온 분야이다. 그러나 지하정보에 대한 연구는 지하정보의 비가시적인 특성상 현재 초기단계라고 할 수 있다. 본 논문은 탄성파를 이용하여 얻어진 지하 지층구조 정보에서 지층대를 식별하고, 공간자료구조를 활용하여 지하 단층대를 분석하고 검색하는 시스템 개발 방법을 제안하고 이와 관련된 사항을 기술하였다. 지하 단층대의 확인 작업은 다양한 지상/지하 구조물의 안정성에 중요한 역할을 하는 자료가 된다. 공간자료구조를 활용하여 지하지층을 인식하는 시스템의 개발은 지질 전문가의 해석을 위한 전처리 시스템으로서 중요한 역할을 할 것이다.

• Magazine of the Korea Concrete Institute
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• v.14 no.2
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• pp.70-76
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• 2002

지하철, 고속철도, 신공항, 공동구, 지하보도, 지하차도, 하수도, 도로 및 철도 등 의 지하구조에는 일반적으로 박스형태의 콘크리트 구조물이 건설되고 있다. 1990년 대 중반 이후 시공 및 사용중인 지하 박스 콘크리트 구조물의 균열 및 누수 등의 문제점이 사회적인 문제로 부각되기 시작하였다. 이러한 지하 박스 콘크리트 구조물에 발생할 수 있는 문제점은 크게 결함(defect), 손상(damage), 열화(deterioration)의 3가지로 구분될 수 있으며, 이들 원인은 구조물에 균열(cracking), 누수(leakage), 처짐(deflection), 부동침하(settlement) 재료분리(segregation) , 박리(delamination), 부식(corrosion), 박락(spalling)등의 현상으로 나타난다.(중략)

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.1
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• pp.23-38
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• 2018

Up to now, most of studies on seismic analysis have been limited to analyze buildings and underground structures individually so that the interaction between them could not be analyzed effectively. Thus, in this study, a dynamic analysis was conducted for soil-structure interaction with a complex underground facility composed of a building and an adjacent underground structure constructed on a surface soil and the bed rock ground conditions. Seismic stability was analyzed based on interstory drift ratio and bending stress of structure members. As a result, an underground structure has more effect on a high-rise building than a low-rise building. However the above structures were proved to be favorable for seismic stability. On the other hand, tensile bending stresses exceeded the allowable value at the underground part of the building and the adjacent underground structure so that it turned out that the underground part could be weaker than the above part. Therefore, it is inferred that above and underground structures should be analyzed simultaneously for better prediction of their interaction behavior during seismic analyses because there exist various structures around buildings in big cities.

• The Journal of the Convergence on Culture Technology
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• v.10 no.1
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• pp.565-570
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• 2024

Recently, due to adjacent excavation work such as new buildings and common tunnel expansion concentrated around the urban railway, deformation of the underground box and tunnel structure of the urban railway built underground has occurred, and as a result, repair and reinforcement work is frequently carried. In addition, the subway is responsible for large-scale transportation, so ensuring the safety and drivability of underground structures is very important. Accordingly, an automated measurement system is being introduced to manage the safety of underground box structures. However, there is no analysis of structural damage vulnerabilities caused by subsidence or uplift of underground box structures. In this study, we aim to analyze damage vulnerabilities for safety monitoring of underground box structures. In addition, we intend to analyze major core monitoring locations by modeling underground box structures through numerical analysis. Therefore, we would like to suggest sensor installation locations and damage vulnerable areas for safety monitoring of underground box structures in the future.

• Proceedings of the Korea Multimedia Society Conference
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• 2003.11a
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• pp.191-194
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• 2003

공간정보의 처리는 방대한 양의 자료처리가 필수적이므로 이를 지원할 수 있는 하드웨어와 소프트웨어의 발전과 함께 최근에 비약적인 발전을 가져온 분야이다. 공간자료구조를 활용한 지리정의시스템(GIS)에 의한 공간정의의 분석과 처리는 근래에 많은 응용을 갖는 분야로서 자리를 잡고 있으며 파생되는 응용분야가 날로 증가하고 있는 추세에 있다. 그러나 지하정보에 대한 연구는 지하정보의 비가시적인 특성상 아직은 초기단계라고 할 수 있다. 특히 지하 지층 분포를 체계적으로 분석하기 위한 연구는 지하 광물자원에 대한 정보 또는 지상의 구조물에 대한 안전성 평가에 대단히 중요한 역할을 한다. 본 논문은 탄성파를 이용하여 얻어진 지하 지층구조를 공간자료구조를 활용하여 분석하는 시스템 개발 방법을 제안하고 이와 관련된 사항을 기술하였다. 공간자료구조를 활용하여 지하지층을 인식하는 시스템의 개발은 지질 전문가의 해석을 위한 전처리 시스템으로서 중요한 역할을 할 것이다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.18 no.1
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• pp.95-107
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• 2016

Ground water is one of important parameters in the designs of underpass structures because urban areas are characterized by soil ground which is relatively permeable than rock ground and a high level of ground water due to low elevation. Therefore, it is important properly to predict variations of the ground water when they can affect underpass structures. In this study, a series of numerical analyses are performed to predict the variations of ground water levels considering the degree of surface imperviousness and LID(Low Impact Development) application. In turn the stability of underground structure is assessed using predicted ground water level. The results show that an increase in the impervious surface area decreases the ground water level. The application of permeable pavement as a LID facility increases the ground water level, improving the infiltration capacity of rainfall into the ground. Seasonal variations of the ground water level are also verified in numerical simulation. The results of this study suggest that reasonable designs of underpass structures can be obtained with the suitable prediction and application of the ground water level considering the surface characteristics.

• Journal of Korean Tunnelling and Underground Space Association
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• v.5 no.2
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• pp.101-113
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• 2003

Nowadays, the construction of new ground structures, which can influence the stability of existing underground structures, is increasing. Consequently, many technical problems occur during the design and construction stage of the new structures. In constructing a neighboring structure, reasonable design and construction is strongly required to balance between the stability of the existing underground structures and the economy of construction of the new structure in terms of the importance of the existing underground structures. Many researches have been performed to estimate the safe region and behavior of underground structures. Constructing a new ground structure above the existing underground structure, external loads are to be applied to the existing underground structure. In this study, therefore, the stability and safe region of the existing underground structure was re-established with respect to the relative location of the new ground structure with the underground structure, the depth from surface to top of the underground structures, and ground conditions.