• Title/Summary/Keyword: Geotechnical buried structure

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Liquefaction-Induced Uplift of Geotechnical Buried Structures: Centrifuge Modeling and Seismic Performance-Based Design (지반 액상화에 의한 지중 매설구조물의 부상: 원심모형시험 및 내진성능설계)

  • Kang, Gi-Chun;Iai, Susumu
    • Journal of the Korean Geotechnical Society
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    • v.28 no.10
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    • pp.5-16
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    • 2012
  • Geotechnical buried structures with relatively light weight have been suffering from uplift damage due to liquefaction in the past earthquakes. The factor of safety approach by Koseki et al. (1997a), which is widely used in seismic design, predicts the triggering of uplift. However, a method for "quantitative" estimates of the uplift displacement has yet to be established. Estimation of the uplift displacement may be an important factor to be considered for designing underground structures under the framework of performance-based design (ISO23469, 2005). Therefore, evaluation of the uplift displacement of buried structure in liquefied ground during earthquakes is needed for a performance-based design as a practical application. In order to predict the uplift displacement quantitatively, a simplified method is derived based on the equilibrium of vertical forces acting on buried structures in backfill during earthquakes (Tobita et al., 2012). The method is verified through comparisons with results of centrifuge model tests and damaged sewerage systems after the 2004 Niigata-ken Chuetsu, Japan, earthquake. The proposed flow diagram for performance-based design includes estimation of the uplift displacement as well as liquefaction limit of backfill.

Behavior of Buried Geo-structures due to Increase of Excess Pore Water Pressure Ratio During Earthquakes (지진발생시 과잉간극수압비의 증가에 따른 지중 매설구조물의 거동)

  • Kang, Gi-Chun
    • Journal of the Korean Geotechnical Society
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    • v.27 no.12
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    • pp.27-37
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    • 2011
  • Uplift phenomenon occurs when the apparent unit weight of buried geo-structures becomes smaller than that of the liquefied backfill due to the increase of an excess pore water pressure during strong earthquakes. In order to explain the relationship between the uplift displacement of the buried geo-structures and the increase of the excess pore water pressure ratio in backfill, dynamic centrifuge model tests are conducted. In the present study, primary and secondary factors against uplift behavior of the buried geo-structures are considered in the dynamic centrifuge model tests. Among these factors, the most important factors affecting the increase in the excess pore water pressure ratio were the ground water depth, the relative density of backfill, and the amplitude of the input acceleration, which were also largely affect the uplift amount of the buried geo-structures.

Assessment of Lifeline Construction Technology for Buried Alive in Building Collapse (도심지 붕괴사고에 따른 매몰지역 생명선 시공기술 평가)

  • Ryu, Byung-Hyun;Kang, Jae-Mo;Lee, Jangguen;Kim, Young-Sam;Joo, Rak-Bong
    • Journal of the Korean GEO-environmental Society
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    • v.17 no.9
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    • pp.47-52
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    • 2016
  • Unusual extreme weather events, which exceed a safe design capacity of the infrastructure, increase the frequency of natural disasters and has also been enlarged damage scale. Aging buildings and rapid urban progress act as weighting factors for the new composite disasters. Technological advances support detecting pre-disaster risk, real-time data analysis, and rapid response to the disaster site, but it is insufficient that emergency relief for buried alive must take advantage of the proven technologies through field tests. This study aims to evaluate directional drilling performance through underground soils and the reinforced concrete structure for primary lifeline installation in order to quickly provide relief supplies for buried alive when urban structures collapse.

A Study on the Determination of Design Load for Buried Hume Pipeline (매설흄관의 설계하중 결정에 관한 연구)

  • O, Chi-Nam;Jeong, Seong-Gyo;Jang, Gi-Tae
    • Geotechnical Engineering
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    • v.5 no.2
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    • pp.19-32
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    • 1989
  • The vertical loads of buried Hume pipes were calculated using the finite element method, in which the hyperbolic soil model, the nonlinear hysteretic stress path model and soil-structure interface model were used. The obtained results were compared and discussed with those from the classic methods such as Marston-Spangler's theory and so on. The effects of excavation width and depth to the top of pipe along with soil parameters and type of excavation, which have not been included in the classic methods, were investigated. In addition, a calculation method of the vertical load for buried Hume pipes was proposed and it is presumed to be easily applied in the practical fields.

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Numerical Analysis of Ground Shock Attenuation from Explosive Loading (폭발하중으로 부터 지반의 완충적 동과에 대한 수치해석적 연구)

  • 박종관
    • Geotechnical Engineering
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    • v.4 no.4
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    • pp.19-28
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    • 1988
  • An underground explosion crests shock waves, which propagate to a buried structure through the이 ground. Due to the explosion, very high stresses and large deformation occur in the ground so that the shock waves decay gradually. In this study the numerical simulation of the ground shock attenuation has teen performed. One dimensional wave equation is presented and the finite difference method is applies. A Cap model is adopted to describe the stress-strain behavior of the ground. The results are expressed by the attenuation of the peak stress and the particle vrelocity by the time and the distance.

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Interaction between Flexible Buried Pipe and Surface Load

  • Yoo, Chung-Sik;Chung, Suk-Won;Lee, Kwang-Myung;Kim, Joo-Suk
    • Journal of the Korean Geotechnical Society
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    • v.15 no.3
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    • pp.83-97
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    • 1999
  • This paper presents the results of a parametric study on the interaction between buried pipes and surface load using the finite element method of analysis. A series of laboratory model tests were also performed in order to validate the adopted finite element model and to capture essential features of the physical behavior of buried pipes subjected to surface load. In the parametric study, a wide range of boundary conditions were analyzed with emphasis on the response of the buried pipes to surface load. The results of analysis such as contact stress distribution at the soil/pipe interface and axial thrust of the pipe were thoroughly analyzed, and a database on the response of buried pipe under surface load was established for future development of a semi-empirical design/analysis method. The results indicated that the degree of interaction between buried pipes and surface load significantly varies with the vertical and lateral location of pipe with respect to surface load, and that the current design method, which does not consider soil-structure interaction, cannot correctly capture the pipe response to surface loading. Furthermore, based on the results of analysis, a semi-empirical equation was suggested, which estimates the maximum pipe thrust due to surface load for flexible buried pipes.

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Prediction and Field Measurement on Behaviour of Soft Clay during Deep Excavation (연약점성토지반에서의 깊은굴착에 따른 지반거동의 예측과 현장계측)

  • 정성교;조기영;정은용
    • Journal of the Korean Geotechnical Society
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    • v.15 no.5
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    • pp.111-124
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    • 1999
  • When deep excavation adjacent to an existing structure is performed, it is very important to minimize damage on the structure through the prediction of ground movement. In this paper, finite element analysis was performed to predict the ground movement, based on the data from site investigation and laboratory tests, when deep excavation close to a buried water tank was carried out in soft clay ground. The movement and stabilities of the soil-cement wall(SCW) and the adjacent structure were checked using the results of the analysis and the field measurement. The comparison between the measured and the predicted ground movements showed the significance of the excavation procedure and lowering of water level in the analytical model. In the future, it is needed to improve the prediction method for better estimation of the ground movement.

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Archaeological Investigations in Urban Areas through Combined Application of Surface ERT and GPR Techniques

  • Papadopoulos, Nikos;Yi, Myeong-Jong;Sarris, Apostolos;Kim, Jung-Ho
    • 한국지구물리탐사학회:학술대회논문집
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    • 2008.10a
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    • pp.113-118
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    • 2008
  • Among the geophysical methods, Ground Penetrating Radar (GPR) and Electrical Resistivity Tomography (ERT) comprise the most promising techniques in resolving buried archaeological structures in urban territories. In this work, two case studies which involve an integrated geophysical survey employing the surface three dimensional (3D) ERT and GPR techniques, in order to archaeologically characterize the investigated areas, are presented. Totally more than 4000 square meters were investigated from the test field sites, which are located at the centre of two of the most populated cities of the island of Crete, in Greece. The ERT and the GPR data were collected along dense and parallel profiles. The subsurface resistivity structure was reconstructed by processing the apparent resistivity data with a 3D inversion algorithm. The GPR sections were processed with a systematic way applying specific filters to the data in order to enhance their information context. Finally, horizontal depth slices representing the 3D variation of the physical properties were created and the geophysical anomalies were interpreted in terms of possible archaeological structures. The subsequent excavations in one of the sites verified the geophysical results, enhancing the applicability of ERT and GPR techniques in the archaeological exploration of urban territories.

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Numerical Simulation for Prediction of Existing Cavity Location on Explosion-Induced Building Collapse (폭발에 의한 건축물 붕괴 시 매몰공동 위치 예측에 관한 수치해석 사례 연구)

  • Jung, Jahe;Park, Hoon;Kim, Kwang Yeom;Shin, Hyu-Soung
    • Journal of the Korean Society of Safety
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    • v.30 no.6
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    • pp.94-101
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    • 2015
  • When a severe disaster such as a building collapse occurs, a first priority for rapid rescue is to find a location where people are highly expected to be buried but alive. It is, however, very difficult to correctly designate the location of such cavities by conventional geophysical survey due to a pile of debris of building members. In this study, location of possible lifeguard cavities were evaluated through a series of simulations of building collapse by explosion depending on the height of the building, a structure of basement floor and a location of explosion. Three types of building structure: five-story, ten-story and fifteen-story were prepared as a model for the simulation. As a results, in the case of low building, only basement floor partially collapsed. On the other hand, in the case of high building, a collapsed range on the inside of the building increased and lifeguard spaces were formed only in the lateral side or corner of the building. In addition, when a wall exists in the basement floor, the possibility that cavities could be formed increased compared to the cases without wall. However, for the fifteen-story building case, no possible lifeguard cavity was found. It is noted that for a high rise building, the height of building more affect forming of safeguard cavity than the structure of the basement floor.