• Title, Summary, Keyword: 3-D numerical analysis

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A Study on the Application of Load Distribution Factor through the Three-Dimensional Numerical Analysis in Tunnel (터널의 3차원 수치해석에서 하중분배율 적용에 관한 연구)

  • Yoon, Won-Sub;Cho, Chul-Hyun;Park, Sang-Jun;Kim, Jong-Kook;Chae, Young-Su
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.784-791
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    • 2008
  • In this study, we recognized about application of the load distribution factor for design of tunnel in 3D numerical analysis. Generally, load distribution factor of tunnel is applied to describe 3D arching effect that can not describe when 2D numerical analysis. Through result of 3D numerical analysis, we used to apply in numerical analysis for the load distribution factor that ratio of finally displacement to displacement of construction step. But 3D numerical analysis need to apply to load distribution factor for convenience of numerical analysis. Therefore, we proposed load distribution factor that reduce time and coast. It corrected variable of advanced length in load distribution factor of 3D numerical analysis.

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Accuracy Improvement of Analysis Results Obtained from Numerical Analysis Model of Continuously Reinforced Concrete Pavement (연속철근 콘크리트 포장 수치해석 모델의 해석결과 정확도 개선 방법)

  • Cho, Young Kyo;Seok, Jong Hwan;Choi, Lyn;Kim, Seong-Min
    • International Journal of Highway Engineering
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    • v.18 no.1
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    • pp.73-83
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    • 2016
  • PURPOSES : The purpose of this study is to develop a method for improving the accuracy of analysis results obtained from a two-dimensional (2-D) numerical analysis model of continuously reinforced concrete pavement (CRCP). METHODS : The analysis results from the 2-D numerical model of CRCP are compared with those from more rigorous three-dimensional (3-D) models of CRCP, and the relationships between the results are recognized. In addition, the numerical analysis results are compared with the results obtained from field experiments. By performing these comparisons, the calibration factors used for the 2-D CRCP model are determined. RESULTS : The results from the comparisons between 2-D and 3-D CRCP analyses show that with the 2-D CRCP model, concrete stresses can be overestimated significantly, and crack widths can either be underestimated or overestimated by a slight margin depending on the assumption of plane stress or plane strain. The behaviors of crack width in field measurements are comparable to those obtained from the numerical model of CRCP. CONCLUSIONS : The accuracy of analysis results from the 2-D CRCP model can be improved significantly by applying calibration factors obtained from comparisons with 3-D analyses and field experiments.

Design of initial support required for excavation of underground cavern and shaft from numerical analysis

  • Oh, Joung;Moon, Taehyun;Canbulat, Ismet;Moon, Joon-Shik
    • Geomechanics and Engineering
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    • v.17 no.6
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    • pp.573-581
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    • 2019
  • Excavation of underground cavern and shaft was proposed for the construction of a ventilation facility in an urban area. A shaft connects the street-level air plenum to an underground cavern, which extends down approximately 46 m below the street surface. At the project site, the rock mass was relatively strong and well-defined joint sets were present. A kinematic block stability analysis was first performed to estimate the required reinforcement system. Then a 3-D discontinuum numerical analysis was conducted to evaluate the capacity of the initial support and the overall stability of the required excavation, followed by a 3-D continuum numerical analysis to complement the calculated result. This paper illustrates the application of detailed numerical analyses to the design of the required initial support system for the stability of underground hard rock mining at a relatively shallow depth.

Static Behavior of Reinforced Railway Roadbed by Geotextile Bag (지오텍스타일 백으로 보강된 철도노반의 정적거동 분석)

  • Lee, Dong-Hyun;Shin, Eun-Chul
    • Journal of the Korean Society for Railway
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    • v.9 no.2
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    • pp.180-186
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    • 2006
  • In this study, a large-scale laboratory model test, 2-D and 3-D numerical analyses were conducted to verify the reinforcement effect by utilizing geotextile bag on the railway roadbed. Static loading which simulated train load was applied on the geotextile bag-reinforced railway roadbed and also unreinforced railway roadbed, Computer program named Pentagon which is a part of FEM programs was used in the numerical analysis. Based on the results of laboratory test, 2-D and 3-D numerical analyses, the effect of load distribution and settlement reduction was found to be depending on the geotextile characteristics, tensile strength of geotextite, and interface friction angle between geotextile bags. In general, the result of 2-D and 3-D numerical analyses shows lower value than that of laboratory test. Also, the result of 3-D numerical analyses shows lower value than that of 2-D numerical analyses because of its stress transfer effect.

A Study on the Rational Application of 3D Numerical Analysis for Anchored Earth Retaining Wall (앵커지지 흙막이 벽체의 합리적인 3차원 수치해석기법 적용에 관한 연구)

  • Jeong, Sang-Seom;Sim, Jae-Uk;Lee, Sung-June
    • Journal of the Korean Geotechnical Society
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    • v.32 no.4
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    • pp.29-39
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    • 2016
  • This paper presents the results of 2D and 3D finite element simulations conducted to analyze the effects of excavation depth (H), excavation width (L), and ground condition on the behavior of anchored earth retaining wall in inclined ground layers. The results of numerical analyses are compared with those of the site instrumentation analyses. Based on the results obtained, it appeared that 2D numerical analysis tends to overestimate the horizontal displacement of retaining wall compared to the 3D numerical analysis. When the excavation depth is deeper than 20m, it is found that 2D and 3D numerical analysis results of excavation work in soil ground condition are more different from the results in rock ground condition. For an accurate 3D numerical analysis, applying 3D mesh which has an excavation width twice longer than excavation depth is recommended. Consequently, 3D numerical analysis may be able to offer significantly better predictions of movement than 2D analysis.

Numerical Analysis of Eddy Currant Testing with Three Dimensional cracked Pipe by using Finte Element Method (유한요소법을 이용한 3차원 관결함의 와전류탐상 수치해석)

  • Won, Sung-Yean;Lee, Hyang-Beom;Shin, Young-Gil
    • Proceedings of the KIEE Conference
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    • pp.220-222
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    • 1999
  • This paper presents a numerical analysis of the eddy current testing with cracked pipe using finite element method (FEM). ${\vec{A}},\;{\phi}-{\vec{A}}$ method is adopted for the formulation of 3-dimensional(3-D) FEM with the brick element. The cracks investigated here are the inner and outer surface of axial symmetry, 90 degree circular one. The algorithm of 3-D numerical analysis is employed for the axisymmetric pipe with the cracks. In order to verify the validity of 3-D numerical analysis, the results are compared with those of 2-D analysis with the same type of the model. The differential impedance is obtained by using energy method and its locus are various 8-shaped curves for each cracks. The ICCG method is used for the calculation of a matrix.

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A Study on the Flow Characteristics in Urban Stream Using 3-D Numerical Model (3차원 수치모형을 이용한 도시하천의 흐름특성에 관한 연구)

  • Yoon, Sun-Kwon;Kim, Jong-Suk;Moon, Young-Il;Lee, Il-Ju
    • Proceedings of the Korea Water Resources Association Conference
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    • pp.1287-1292
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    • 2007
  • Recently, the frequency of unexpecting heavy rains has been increased due to abnormal climate and extreme rainfall. There was a limit to analyze 1D or 2D stream flow that was applied simple momentum equation and fixed energy conservation. Therefore, hydrodynamics flow analysis in rivers has been needed 3D numerical analysis for correct stream flow interpretation. In this study, CFD model on FLOW-3D was applied to stream flow analysis, which solves three dimenson RANS(Reynolds Averaged Navier-Stokes Equation) control equation to find out physical behavior and the effect of hydraulic structures. Numerical simulation accomplished those results was compared by using turbulence models such as ${\kappa}-{\varepsilon}$, RNG ${\kappa}-{\varepsilon}$ and LES. Those numerical analysis results have been illustrated by the turbulence energy effects, velocity of flow distributions, water level pressure distributions and eddy flows around the piers at Jangwall bridge in urbarn stream.

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3D Characteristics of Dynamic Response of Seabed around Submerged Breakwater Due to Wave Loading (파랑하중에 의한 잠제 주변 해저지반의 3차원 동적응답 특성)

  • Hur, Dong-Soo;Park, Jong-Ryul;Lee, Woo-Dong
    • Journal of Ocean Engineering and Technology
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    • v.28 no.4
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    • pp.331-337
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    • 2014
  • We analyzed the 3-D characteristics of the dynamic response of seabed around a submerged breakwater due to wave loading using a 3-D numerical scheme (LES-WASS-3D). Using our model, which considers the wave-structure-sandy seabed interactions in a 3-D wave field, we were able to investigate the 3-D characteristics of the pore-water pressure in the seabed around the submerged breakwater under various incident wave conditions. To verify the 3-D numerical analysis method suggested in this study, we compared the numerical results with the existing experimental results and found good agreement between them. The numerical analysis reveals that high pore-water pressure in the seabed is generated below a large wave height at the front slope of the submerged breakwater. It was also shown that the non-dimensional pore-water pressure in the seabed increases as the wave period increases because the wave energy dissipation decreases on the submerged breakwater and seabed as the wave period increases.

3D FE Analysis of Cast-in-situ Concrete Pile embedded in Weathered Rock (풍화암에 지지된 현장타설말뚝의 3차원 해석)

  • Kim, Sang-Baek;Lee, Whaol;Kwon, Oh-Kyun;Choi, Yong-Kyu
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.167-172
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    • 2000
  • In this study, the behaviors of a cast-in-situ concrete pile embedded in the weathered rock were analysed by a 3D numerical analysis using PENTAGON 3D and the results were compared with those of the field load test. The load-settlement relation and the load transfer relationship were evaluated from the numerical analysis. As a result, the load-settlement relation at the pile top and the axial load distribution with depth were predicted reasonably. And those results were similar with those of the field load test.

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Precision of predicted 3D numerical solutions of vortex-induced oscillation for bridge girders with span-wise varying geometry

  • Harada, Takehiko;Yoshimura, Takeshi;Tanaka, Takahisa;Mizuta, Yoji;Hashiguchi, Takafumi;Sudo, Makoto;Miyazaki, Masao
    • Wind and Structures
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    • v.7 no.1
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    • pp.13-28
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    • 2004
  • A method of numerical analysis without conducting 3D wind tunnel model tests was examined in our previous study for predicting vortex-induced oscillation of bridge girders with span-wise varying geometry. The aerodynamic damping forces measured for plural wind tunnel 2D models were used in the analysis. A further study was conducted to examine the precision of solution obtained by this method. First, the responses of vortex-induced oscillation of two rocking models and a taut-strip bridge girder model with span-wise varying geometry were measured. Next, the responses of these models were numerically analyzed by means of this method, and then a comparison was made between the obtained $Vr-A-{\delta}_a$ contour diagram of each 3D model in the wind tunnel test and the diagram in the numerical analysis. Since close correlations were observed between each two $Vr-A-{\delta}_a$diagrams obtained in the model test and in the analysis in cases where the 3D model did not have strong three-dimensionality, our findings revealed that the predicted solution proved to be reasonably accurate.