• 제목/요약/키워드: Geological model

검색결과 551건 처리시간 0.031초

Effects of spatial variability of earthquake ground motion in cable-stayed bridges

  • Ferreira, Miguel P.;Negrao, Joao H.
    • Structural Engineering and Mechanics
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    • 제23권3호
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    • pp.233-247
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    • 2006
  • Most codes of practice state that for large in-plane structures it is necessary to account for the spatial variability of earthquake ground motion. There are essentially three effects that contribute for this variation: (i) wave passage effect, due to finite propagation velocity; (ii) incoherence effect, due to differences in superposition of waves; and (iii) the local site amplification due to spatial variation in geological conditions. This paper discusses the procedures to be undertaken in the time domain analysis of a cable-stayed bridge under spatial variability of earthquake ground motion. The artificial synthesis of correlated displacements series that simulate the earthquake load is discussed first. Next, it is described the 3D model of the International Guadiana Bridge used for running tests with seismic analysis. A comparison of the effects produced by seismic waves with different apparent propagation velocities and different geological conditions is undertaken. The results in this study show that the differences between the analysis with and without spatial variability of earthquake ground motion can be important for some displacements and internal forces, especially those influenced by symmetric modes.

GIS-based Metallogenic Prognosis of Lead-Zinc Deposits in China

  • Tang, Panke;Wang, Chunyan
    • 한국컴퓨터정보학회논문지
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    • 제20권12호
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    • pp.91-99
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    • 2015
  • In this paper, we introduce the application of several currently-representative methods for mineral resources potential assessment on Geographic information system(hereinafter referred to as GIS), and combined with mineral resources potential assessment performed in China and with lead-zinc deposits taken as an example, summarized and divided minerals prediction and assessment models; on this basis, this paper presented the process of metallogenic prognosis based on MRAS platform, and made a simple analysis on existing problems.

Development of a multiphysics numerical solver for modeling the behavior of clay-based engineered barriers

  • Navarro, Vicente;Asensio, Laura;Gharbieh, Heidar;la Morena, Gema De;Pulkkanen, Veli-Matti
    • Nuclear Engineering and Technology
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    • 제51권4호
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    • pp.1047-1059
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    • 2019
  • This work describes the development of a numerical module with a multiphysics structure to simulate the thermo-hydro-chemo-mechanical behavior of compacted bentonites. First, the conceptual model, based on the state-of-the-art formulation for clay-based engineered barriers in deep geological repositories, is described. Second, the advantages of multiphysics-based modules are highlighted. Then, the guidelines to develop a code using such tools are outlined, presenting an example of implementation. Finally, the simulation of three tests that illustrate the behavior of compacted bentonites assesses the scope of the developed code. The satisfactory results obtained, and the relative simplicity of implementation, show the opportunity of the modeling strategy proposed.

탄성파 간섭파를 이용한 중합전 구조보정 (Prestack migration using seismic interferometry)

  • 김영완;장성형;윤왕중;서상용
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2008년도 추계학술대회 논문집
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    • pp.203-207
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    • 2008
  • Prestack depth migration is used to image for complex geological structure such as faults, folds, and subsalt. In this case, it is widely used the surface reflection data as a input data. However, the surface reflection data have intrinsic problems to image the subsalt and the salt flank due to the complex wavefields and multiples which come from overburden. For overcoming the structural defect of the surface reflection data in the imaging, I used the virtual sources in terms of seismic interferometry to image the subsurface and suppress the multiples using the velocity model of the lower part of the virtual sources. The results of the prestack depth migration using virtual source gathers and velocity model below receivers are similar geological interfaces to the results from shot gathers of the conventional ocean bottom seismic survey. And especially artificial interfaces by multiples were suppressed without applying any other data processing to eliminate multiples. This study results by numerical modeling can make a valuable imaging tool when it is applied to satisfied field data for specific condition.

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전기비저항에 의한 지중저장 이산화탄소 거동관측 모의실험 (Electrical resistivity monitoring of a scale model experiment for geological $CO_2$ sequestration)

  • 박미경;장한누리;김희준;왕수균;이민희
    • 한국지구물리탐사학회:학술대회논문집
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    • 한국지구물리탐사학회 2007년도 공동학술대회 논문집
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    • pp.173-178
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    • 2007
  • Time-lapse electrical resistivity measurements have been made in a scale model experiment for geological $CO_2$ sequestration in aquifer. Three types of $CO_2$ injection are tested in a water tank filled with glass beads. These are $CO_2$ dissolved into filtered tap water, $CO_2$ gas, and mineral oil. The mineral oil is a substitute for liquid phase of supercritical $CO_2$. For reconstructing three-dimensional resistivity images, we measure potential differences at 32 potential dipoles on the top surface of the tank due to two current dipoles on the front and back sides. The resultant resistivity images clearly show the movement of injected $CO_2$ in aquifer.

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Modeling the sensitivity of hydrogeological parameters associated with leaching of uranium transport in an unsaturated porous medium

  • Mohanadhas, Berlin;Govindarajan, Suresh Kumar
    • Environmental Engineering Research
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    • 제23권4호
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    • pp.462-473
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    • 2018
  • The uranium ore residues from the legacies of past uranium mining and milling activities that resulted from the less stringent environmental standards along with the uranium residues from the existing nuclear power plants continue to be a cause of concern as the final uranium residues are not made safe from radiological and general safety point of view. The deposition of uranium in ponds increases the risk of groundwater getting contaminated as these residues essentially leach through the upper unsaturated geological formation. In this context, a numerical model has been developed in order to forecast the $^{238}U$ and its progenies concentration in an unsaturated soil. The developed numerical model is implemented in a hypothetical uranium tailing pond consisting of sandy soil and silty soil types. The numerical results show that the $^{238}U$ and its progenies are migrating up to the depth of 90 m and 800 m after 10 y in silty and sandy soil, respectively. Essentially, silt may reduce the risk of contamination in the groundwater for longer time span and at the deeper depths. In general, a coupled effect of sorption and hydro-geological parameters (soil type, moisture context and hydraulic conductivity) decides the resultant uranium transport in subsurface environment.

Deep Hydrochemical Investigations Using a Borehole Drilled in Granite in Wonju, South Korea

  • Kim, Eungyeong;Cho, Su Bin;Kihm, You Hong;Hyun, Sung Pil
    • 방사성폐기물학회지
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    • 제19권4호
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    • pp.517-532
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    • 2021
  • Safe geological disposal of spent nuclear fuel (SNF) requires knowledge of the deep hydrochemical characteristics of the repository site. Here, we conducted a set of deep hydrochemical investigations using a 750-m borehole drilled in a model granite system in Wonju, South Korea. A closed investigation system consisting of a double-packer, Waterra pump, flow cell, and water-quality measurement unit was used for in situ water quality measurements and subsequent groundwater sampling. We managed the drilling water labeled with a fluorescein dye using a recycling system that reuses the water discharged from the borehole. We selected the test depths based on the dye concentrations, outflow water quality parameters, borehole logging, and visual inspection of the rock cores. The groundwater pumped up to the surface flowed into the flow cell, where the in situ water quality parameters were measured, and it was then collected for further laboratory measurements. Atmospheric contact was minimized during the entire process. Before hydrochemical measurements and sample collection, pumping was performed to purge the remnant drilling water. This study on a model borehole can serve as a reference for the future development of deep hydrochemical investigation procedures and techniques for siting processes of SNF repositories.

Sorption of Se(-II) on illite, MX-80 bentonite, shale, and limestone in Na-Ca-Cl solutions

  • Walker, Andrew;Racette, Joshua;Saito, Takumi;Yang, Tammy (Tianxiao);Nagasaki, Shinya
    • Nuclear Engineering and Technology
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    • 제54권5호
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    • pp.1616-1622
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    • 2022
  • Selenium has been identified as an element of interest for the safety assessment of a deep geological repository (DGR) for used nuclear fuel. In Canada, groundwaters at DGR depths in sedimentary rocks have been observed to have a high ionic strength. This paper examines the sorption behavior of Se(-II) onto illite, MX-80 bentonite, Queenston shale, and argillaceous limestone in Na-Ca-Cl solutions of varying ionic strength (0.1-6 mol/kgw (m)) and across a pH range of 4-9. Little ionic strength dependence for Se(-II) sorption onto all solids was observed except that sorption at high ionic strength (6 m) was generally slightly lower than sorption at low ionic strength (0.1 m). Illite and MX-80 exhibited the expected results for anion sorption, while shale and limestone exhibited more constant sorption across the pH range tested. A non-electrostatic surface complexation model successfully predicted sorption of Se(-II) onto illite and MX-80 using the formation of an inner-sphere surface complex and an outer-sphere surface complex. Optimized values for the formation reactions of these surface species were proposed.

수치지형고도자료의 영상처리 (Digital image processing for digital elevation model data)

  • 이봉주;조민호;강필종
    • 지질공학
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    • 제2권2호
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    • pp.141-146
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    • 1992
  • 미국 DMA사에서 제공되고 있는 수치지형고도자료를 이용하여 Shaded Relief Umage와 Landsat TM자료의 Stereo-pair image를 작성하였다. 이는 지형지세의 3차원적 표현 및 관찰을 통한 위성자료로 부터 지질구조 판독의 정확도 및 객관성 제고에 매우 유용하게 활용될 것으로 기대된다.

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불연속 파쇄모델을 이용한 파쇄 매질에서의 지하수 유동 시뮬레이션 (Simulation of Groundwater Flow in Fractured Porous Media using a Discrete Fracture Model)

  • 박유철;이강근
    • 자원환경지질
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    • 제28권5호
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    • pp.503-512
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    • 1995
  • 2차원 불연속 절리 모델 (Discrete Fracture Model)을 사용하여 절리망 내에서 지하수 흐름을 시뮬레이션하였다. 불연속 절리 모델에서는 지하수가 오직 절리망을 통해서 흐른다고 가정한다. 이와 같은 분석은 결정질암 같이 지질 매체의 투수율이 매우 낮은 경우에 유용하다. 하지만 불연속 절리망을 완벽하게 구현하는 것이 불가능하므로, 이에 접근하는 방법으로 확률 통계적 모델이 제안되었다. 확률-통계적 모텔은 특성인자(밀도, 방향, 길이, 틈새두께 등)가 특별한 분포 유형을 갖는다고 가정한다. 확률-통계적 모델은 가정된 분포를 따르도록 특성인자를 생성한다. 이 후 본 모델을 통해 분석된 몇몇 특성인자를 가지고 절리망을 생성한다. 절리망을 생성한 이 후 지하수의 유통을 계산하기 위해 유한요소법을 적용하였다. 이 때 일차원 선요소가 유한요소망의 주요 요소이다. 시뮬레이션 결과는 절리망 내의 주요 흐름 경로를 통해 보여진다. 절리망 내의 지하수 속도를 비교하여 주요 흐름 경로를 찾아낸다. 본 연구에서 개발된 모델은 절리망 내의 지하수 흐름에 특성인자들이 미치는 영향을 평가할 수 있는 방법을 제공한다. 이를 위하여 30번의 생성을 하는 몬테카를로 시뮬레이션을 통해서 여러 특성 인자들이 지하수 흐름에 미치는 영향을 평가하였다.

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