• Title/Summary/Keyword: 3차원 지반모델링

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A Study on Key Factors of Ground Settlement Due to Shield TBM Excavation using Numerical Analysis and Field Measurement Comparison (수치해석과 현장 계측값 비교를 통한 Shield TBM 지표침하 영향요소 검토)

  • Jun, Gychan;Kim, Donghyun
    • Journal of the Korean Geosynthetics Society
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    • v.16 no.1
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    • pp.63-72
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    • 2017
  • This study estimates the degree of influence of factors influencing ground surface settlement during tunnel excavation using Shield tunneling trough 3D FE-analyses. Numerical analysis was carried out by considering face pressure, skinplate pressure, excavation length, soil model, element size and soil material properties. Also, Actually constructed shield TBM comparative analysis was conducted by compared with Volume loss model, Pressure model and field measurement data. Skinplate pressure and soil model were the most influential factors, and the analysis results were similar to field measurements when the appropriate skinplate pressure was applied according to the passing stratum.

Evaluation of Seismic Performance of Takahama Wharf Using Nonlinear Effective Stress Analysis (비선형 유효응력해석을 이용한 Takahama 잔교식 안벽의 내진성능 평가)

  • Tran, Nghiem Xuan;Lee, Jin-sun;Kim, Sung-Ryul
    • Journal of the Korean Geotechnical Society
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    • v.33 no.4
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    • pp.47-56
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    • 2017
  • Aseismic designs of pile-supported wharves are commonly performed utilizing simplified dynamic analyses, such as multi-mode spectral analyses. Simplified analyses can be useful for evaluating the limit state of structures. However, several pile-supported wharves, that have been damaged during past earthquakes, have shown that soil deformation and soil-pile dynamic interaction significantly affect the entire behavior of structures. Such behavior can be captured by performing nonlinear effective stress analyses, which can properly consider the dynamic interactions among the soil-pile-structure. The present study attempts to investigate the earthquake performance of a pile-supported wharf utilizing a three-dimensional numerical method. The damaged pile-supported wharf at the Kobe Port during the Hyogo-ken Nambu earthquake (1995) is selected to verify the applicability of the numerical modeling. Analysis results showed a suitable agreement with the observations on the damaged wharf, and the significant effect of excess pore pressure development and pile-soil dynamic interaction on the seismic performance of the wharf.

3D Modelling of Geological Distributions for the Rock Tunneling Design and the Study for Geostatistical Approaching of the Distributions of Rock Classifications by 3D Krigging (암반터널설계를 위한 지층분포의 3차원 모델링과 3D Krigging 기법을 이용한 암반등급분포의 지구통계학적 처리방안 연구)

  • 배기훈;윤운상;추석연;이상태
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.03a
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    • pp.245-252
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    • 2002
  • The Rock mass in which constructed a tunnel consist of the geological formations or the engineering rock type. Each layers are distinguished by the mineral, weathering and distributions of faults and Joints. Therefore, a tunneling design in rock mass starts from understanding and analyzing of the various geological engineering factors and then the engineering characteristics and distributions for each layers are determined to analysis and collection of the efficient informations. For this working, next two problems have to be solved. First, the layers in rock mass have to be classified and their distributions have to be defined. Second, the rock mass classifications and distributions based on the standard engineering classification have to be determined. Efficiently to approaching this two problems, the best solution is all geotechnical data are embodied to 3-D.

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Numerical Modeling of Large Triaxial Compression Test with Rockfill Material Considering 3D Grain Size Distribution (3차원 입도분포를 고려한 락필재료의 대형삼축압축시험 수치모델링)

  • Noh, Tae Kil;Jeon, Je Sung;Lee, Song
    • Journal of the Korean GEO-environmental Society
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    • v.13 no.10
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    • pp.55-62
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    • 2012
  • In this research, the algorithm for simulating specific grain size distribution(GSD) with large diameter granular material was developed using the distinct element analysis program $PFC^{3D}$(Particle Flow Code). This modeling approach can generate the initial distinct elements without clump logic or cluster logic and prevent distinct element from escaping through the confining walls during the process. Finally the proposed distinct element model is used to simulate large triaxial compression test of the rockfill material and we compared the simulation output with lab test results. Simulation results of Assembly showed very well agreement with the GSD of the test sample and numerical modeling of granular material would be possible for various stress conditions using this application through the calibration.

Numerical Formulation for Flow Analysis of Dredged Soil (준설토 유동해석을 위한 유한요소 수식화)

  • Shin, Hosung
    • Journal of the Korean GEO-environmental Society
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    • v.15 no.3
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    • pp.41-48
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    • 2014
  • Experimental study of sedimentation and self-weight consolidation has been primary research area in dredged soil. However, good quality of the dredged soil and minimum water pollution caused by the pumping of reclaimed soil require intensive study of the flow characteristics of dredged material due to dumping. In this study, continuity and the equilibrium equations for mass flow assuming single phase was derived to simulate mass flow in dredged containment area. To optimize computation and modeling time for three dimensional geometry and boundary conditions, depth integration is applied to governing equations to consider three dimensional topography of the site. Petrov-Galerkin formulation is applied in spatial discretization of governing equations. Generalized trapezoidal rule is used for time integration, and Newton iteration process approximated the solution. DG and CDG technique were used for weighting matrix in discontinuous test function in dredged flow analysis, and numerical stability was evaluated by performed a square slump simulation. A comparative analysis for numerical methods showed that DG method applied to SU / PG formulation gives minimal pseudo oscillation and reliable numerical results.

Evaluation of Liquefaction Model using Dynamic Centrifuge Test (포화된 경사 사질토 지반의 액상화 수치모델 거동평가)

  • Lee, Jin-Sun;Lee, Sang-Un
    • Journal of the Korean Geotechnical Society
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    • v.38 no.11
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    • pp.31-42
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    • 2022
  • This study verified numerical analysis of the liquefaction phenomenon using LEAP-2017 international round-robin centrifuge test results. Dynamic centrifuge test is performed by applying a 1 Hz tapered sine wave to the model soil deposit, which was formed under a water table in a surface slope of 5° using Ottawa F-65 sand. A numerical model was made on a prototype scale and analyzed using the finite difference method in 2D and 3D conditions. The analyses were verified for acceleration and pore-water pressure histories with depth and residual displacement. Verification results revealed that all numerical liquefaction models agree reasonably with the test result for acceleration histories but not for pre-water pressure histories. Numerical analyses showed much smaller residual displacement than the centrifuge test. Thus, it is necessary to compare the results of numerical analysis with the centrifuge test performed by other institutes in the future.

Implementation Method of GIS Map for 3D Liquefaction Risk Analysis (3차원 액상화 위험분석을 위한 GIS Map 구현 방안)

  • Lee, Woo-Sik;Jang, Yong Gu
    • 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.

측압계수에 따른 숏크리트 거동의 수치해석적 검증

  • Yu, Gwang-Ho;Jeong, Ji-Seong;Im, Yeong-Su;Park, Yeon-Jun
    • Proceedings of the Korean Society for Rock Mechanics Conference
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    • 2008.10a
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    • pp.365-376
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    • 2008
  • 본 논문은 1차로 마제형 터널에서의 지반과 지보재의 상호 거동을 규명하기 위한 연구로서 터널의 주지보재인 숏크리트의 균열, 파괴하중 및 변형하는 거동양상을 실물크기의 터널모형실험을 통해 확인하였다. 이때 실험은 측압계수를 0.5, 1.0, 2.0으로 설정하여 각각 측압계수에 따른 결과를 확인하였다. 또한 실제 실험과 같은 조건을 설정한3차원 수치해석을 실시하여 각각의 결과를 비교 검증하였다. 터널모형 실험은 측압조건을 설정할 수 있도록 11개의 실린더를 사용하여 실험을 수행하였다. 3차원 수치해석 모델링은 터널모형실험과 가능하면 같은 조건으로 해석하기 위하여 모형실험으로부터 로드셀 및 LVDT를 통해 얻은 하중-변위곡선이 수치해석 시에도 재현되도록 하였다.

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Application of the Evaluation System of Rock Mass in a Mountain Tunnel Constructed by NATM (NATM 시공 산악터널에서의 암반평가시스템 적용 연구)

  • 김영근;장정범;정한중
    • Tunnel and Underground Space
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    • v.5 no.4
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    • pp.297-307
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    • 1995
  • 터널은 긴 선상구조물로서 사정조사결과와 다른 지질조건이 나타날 수 있으므로, 안전하고 합리적인 터널공사를 위해서는 시공중 지질조건에 적합한 지보설계를 실시하는 것이 필수적이다. 이를 위해서는 시공중 터널주변자반에 대한 정량적이고 공학적인 평가가 매우 중요하다. 그러나 시공중 암반을 평가하는 것은 매우 어렵고 조사자의 경험과 지식의 차이에 의해 평가정도가 크게 달라져 그 불합리성이 심화되고 있는 실정으로 터널주변암반에 대한 합리적인 평가방법이 절실히 요구되고 있다. 본 연구에서는 터널화상처리, GeoCAD, 역해석으로 구성된 평기시스템을 개발하였다. 본 시스템은 터널막장에서의 조사.시험 및 화상처리기법을 통하여 암반분류.평가를 실시하고, 터널주변 지반구조 및 굴착/지보과정의 3차원 모델링을 통하여 전방지질을 예측가능하게 하며, 터널계측자료의 역해석을 통하여 터널주변 지반의 물성을 정량적으로 평가할 수 있는 체계적이고 종합적인 평가시스템이다. 또한 이를 NATM 공법으로 시공되는 터널현장에 적용하므로써 본 시스템의 현장적용성을 검증하였으며, 이를 통해 적절한 지보공을 시공하여 터널의 안정성을 확보하고 합리적인 시공관리를 달성할 수 있었다.

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Analysis of Soil Resistance on Laterally Loaded Piles Considering Soil Continuity (지반의 연속성을 고려한 말뚝의 수평지반저항력 산정)

  • Kim, Young-Ho;Jeong, Sang-Seom
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.30 no.4C
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    • pp.175-183
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    • 2010
  • The load distribution and deflection of large diameter piles are investigated by lateral load transfer method (p-y curve). The emphasis is on the effect of the soil continuity in a laterally loaded pile using 3D finite element analysis. A framework for determining a p-y curve is calculated based on the surrounding soil stress. The parametric studies that take into account the soil continuity are also presented in this paper. Through comparisons with results of field load tests, it is found that the prediction by the present approach is in good agreement with the general trend observed by in situ measurements and thus, represents a significant improvement in the prediction of a laterally loaded pile behavior. Therefore, a present study considering the soil continuity would be more economical pile design.