• Title/Summary/Keyword: 비선형 지반-구조물 상호작용

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Numerical Simulation of Nonlinear Interaction between Composite Breakwater and Seabed under Irregular Wave Action by olaFlow Model (olaFlow 모델에 의한 불규칙파 작용하 혼성방파제-해저지반의 비선형상호작용에 관한 수치시뮬레이션)

  • Lee, Kwang-Ho;Bae, Ju-Hyun;Jung, Uk Jin;Choi, Goon-Ho;Kim, Do-Sam
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.31 no.3
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    • pp.129-145
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    • 2019
  • For the design of composite breakwater as representative one of the coastal and harbor structures, it has been widely discussed by the researchers about the relation between the behavior of excess-pore-water pressure inside the rubble mound and seabed caused by the wave load and its structural failure. Recently, the researchers have tried to verify its relation through the numerical simulation technique. The above researches through numerical simulation have been mostly applied by the linear and nonlinear analytic methods, but there have been no researches through the numerical simulation by the strongly nonlinear mutiphase flow analytical method considering wave-breaking phenomena by VOF method and turbulence model by LES method yet. In the preceding research of this study, olaFlow model based on the mutiphase flow analytical method was applied to the nonlinear interaction analysis of regular wave-composite breakwater-seabed. Also, the same numerical techniques as preceding research are utilized for the analysis of irregular wave-composite breakwater-seabed in this study. Through this paper, it is investigated about the horizontal wave pressures, the time variations of excess-pore-water pressure and their frequency spectra, mean flow velocities, mean vorticities, mean turbulent kinetic energies and etc. around the caisson, rubble mound of the composite breakwater and seabed according to the changes of significant wave height and period. From these results, it was found that maximum nondimensional excess-pore water pressure, mean turbulent kinetic energy and mean vorticity come to be large equally on the horizontal plane in front of rubble mound, circulation of inflow around still water level and outflow around seabed is formed in front of rubble caisson.

Nonlinear Earthquake Response Analysis of 2-D Underground Structures with Soil-Structure Interaction Including Separation and Sliding at Interface (지반-구조물 상호작용계의 경계면에서 미끄러짐과 분리현상을 고려한 이차원 지하구조물의 비선형 지진응답해석)

  • 최준성;이종세;김재민
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2002.04a
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    • pp.174-181
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    • 2002
  • The paper presents an effective analytical method for SSI systems which can have separation or sliding at the soil-structure interface. The method is based on a hybrid approach which combines a linear SSI code KIESSI-2D in frequency domain with a commercial finite element package ANSYS to obtain nonlinear dynamic responses in time domain. The method is applied to a 2-D underground box structure which experiences separation and sliding at the soil-structure interface. Material nonlinearity of the concrete structure is also included in the analysis. Effects of the interface conditions are examined and some critical factors affecting the seismic performance of underground structures are identified.

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Axial Load Capacity Prediction of Single Piles in Clay and Sand Layers Using Nonlinear Load Transfer Curves (비선형 하중전이법에 의한 점토 및 모래층에서 파일의 지지력 예측)

  • Kim, Hyeongjoo;Mission, Joseleo;Song, Youngsun;Ban, Jaehong;Baeg, Pilsoon
    • Journal of the Korean GEO-environmental Society
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    • v.9 no.5
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    • pp.45-52
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    • 2008
  • The present study has extended OpenSees, which is an open-source software framework DOS program for developing applications to idealize geotechnical and structural problems, for the static analysis of axial load capacity and settlement of single piles in MS Windows environment. The Windows version of OpenSees as improved by this study has enhanced the DOS version from a general purpose software program to a special purpose program for driven and bored pile analysis with additional features of pre-processing and post-processing and a user friendly graphical interface. The method used in the load capacity analysis is the numerical methods based on load transfer functions combined with finite elements. The use of empirical nonlinear T-z and Q-z load transfer curves to model soil-pile interaction in skin friction and end bearing, respectively, has been shown to capture the nonlinear soil-pile response under settlement due to load. Validation studies have shown the static load capacity and settlement predictions implemented in this study are in fair agreement with reference data from the static loading tests.

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Nonlinear Soil-Structure Interaction Analysis Considering Complicated Soil Profile (복잡한 지반 형상을 고려한 비선형 지반-구조물상호작용 해석)

  • Park, Jang-Ho
    • Journal of the Korean Society of Safety
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    • v.26 no.1
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    • pp.36-42
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    • 2011
  • This paper presents a nonlinear soil-structure interaction analysis approach, which can consider precisely characteristics of structures, complicated soil profiles and nonlinear characteristics of soil. Although many methods have been developed to deal with the soil-structure interaction effects in past years, most of them are nearly unpractical since it is difficult to model complicated characteristics of structure and soil precisely. The presented approach overcomes the difficulties by adopting an maligned mesh generation approach and multi-linear model. The applicability of the proposed approach is validated and the effects of complicated characteristics of structure and soil on soil-structure interaction are investigated through the numerical example by the proposed nonlinear soil-structure interaction analysis approach.

Analysis of Nonlinear Behaviors of Shotcrete-Steel Support Lining Considering the Axial Force Effects (축력의 영향을 고려한 숏크리트-강지보 합성 라이닝의 비선형 거동 분석)

  • Yu, Jeehwan;Kim, Jeongsoo;Kim, Moon Kyum
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.37 no.2
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    • pp.357-367
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    • 2017
  • Bending and axial forces simultaneously occur at the cross-section of a shotcrete lining reinforced with steel supports due to the tunnel geometry. The shotcrete has changing flexural stiffness depending on the axial forces and, as a result, severely nonlinear behavior. The mechanical properties of a shotcrete-steel composite also depend on the type of steel support. This study presents a fiber section element model considering the effect of axial force to evaluate the nonlinear behavior of a shotcrete-steel composite. Additionally, the model was used to analyze the effects of different types of steel supports on the load capacity. Furthermore, a modified hyperbolic model for ground reaction, including strain-softening, is proposed to account for the ground-lining interaction. The model was validated by comparing the numerical results with results from previous load test performed on arched shotcrete specimens. The changes in mechanical responses of the lining were also investigated. Results show a lining with doubly reinforcement rebar has similar load capacity as a lining with H-shaped supports. The use of more materials for the steel support enhances the residual resistance. For all types of steel reinforcement, the contribution of steel supports during peak load decreases as the ground becomes stiffer.

Parameter Identification and Nonlinear Seismic Analysis of Soil-Structure Interaction System (지반-구조물 상호작용계의 계수추정 및 비선형 지진응답해석)

  • 윤정방
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 1997.04a
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    • pp.265-272
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    • 1997
  • This paper presents the result of an international cooperative research on the post-correlation analysis of forced vibration tests and the prediction of earthquake responses of a large-scale seismic test structure. Through the post-correlation analysis, the properties of the soil layers are revised so that the best correlation in the responses may be obtained compared with the measured force vibration test data. Utilizing the revised soil properties as the initial linear values, the seismic responses are predicted for an earthquake using the equivalent linearlization technique based on the specified strain dependent characteristics of the shear moduli and damping ratios. It has been found that the predicted responses by the equivalent nonlinear procedure are in excellent agreement with the observed responses, which those using the initial properties are fairly off from the measured results.

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Dynamic Analysis of Mooring Dolphin System Considering Soil Properties (지반의 강성특성을 고려한 지반-돌핀구조계의 동적해석)

  • Yi, Jin-Hak;Oh, Se-Boong;Yun, Chung-Bang;Hong, Sup;Kim, Jin-Ha
    • Journal of Ocean Engineering and Technology
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    • v.12 no.3 s.29
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    • pp.19-30
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    • 1998
  • In this paper, the dynamic analysis of a dolphin system for mooring a floating structure such as barge mounted plant is studied. The characteristics of the soil-pile system are simplified by a set of equivalent spring elements at the mudline. To evaluate the equivalent spring constants, the finite difference method is used. Since the characteristics of the soil-pile system are nonlinear in case of soft foundation, the nonlinear dynamic analysis technique is needed. The Newmark $beta$ method incorporating the modified Newton-Raphson method(initial stiffness method) is used. A numerical analysis is performed on two mooring dolphin systems on soft foundation and rock foundation. In case of the rock foundation, the characteristics are found to be nearly linear, so the linear dynamic analysis may be sufficient to consider the foundation effect. But in case of soft foundation, the non-linearity of the foundation appears to be very signigicant, so the nonlinear dynamic analysis si needed.

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Stochastic Analysis in the Generation of Floor Response Spectra for Liner Systems with Proportional Damping (추계학적(推計學的) 해석법(解析法)에 의한 선형비례감쇠(線形比例減衰) 시스템의 층응답(層應答)스펙트럼)

  • Park, Young Suk;Seo, Jeong Moon
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.8 no.1
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    • pp.77-85
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    • 1988
  • A stochchastic analysis procedure of generating floor response spectra for proportionally damped linear systems subject to earthquake loading is presented. Theories of random vibration and mode acceleration method are used in the formulation of governing equations. The structure-oscillator interaction is not considered. It is assumed that the input motions and oscillator responses are stationary Gaussian processes with mean zero. The nonstationary characteristics of earthquake motion are incorporated in the peak factor which is based on Vanmarcke's theory. Floor response spectra for both resonance and non-resonance cases are calculated under the assumption that the peak factors for structure and oscillator are equal to that for ground response spectrum. The validity of this method is demonstrated by comparing the results obtained by proposed method with those by time history analyses. The results obtained by this method are conservative and accurate with tolerable precision. This method saves much computing time compared with time history analysis method.

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Dynamic Change of Stresses in Subsoil under Concrete Slab Track Subjected to Increasing Train Speeds (열차 증속에 따른 콘크리트 궤도 노반의 동적 응력 변화)

  • Lee, Tae-Hee;Choi, Chan-Yong;Nsabimana, Ernest;Jung, Young-Hoon
    • Journal of the Korean Geotechnical Society
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    • v.29 no.10
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    • pp.57-66
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    • 2013
  • Societal interest on a faster transportation demands an increase of the train speed exceeding current operation speed of 350 km/h. To trace the pattern of variations in displacements and subsoil stresses in the concrete slab track system, finite element simulations were conducted. For a simple track-vehicle modeling, a mass-point system representing the moving train load was developed. Dynamic responses with various train speeds from 100 to 700 km/h were investigated. As train speeds increase the displacement at rail and subsoil increases nonlinearly, whereas significant dynamic amplification at the critical velocity has not been found. At low train speed, the velocity of elastic wave carrying elastic energy is faster than the train speed. At high train speed exceeding 400 km/h, however, the train speed is approximately identical to the elastic wave velocity. Nonlinearity in the stress history in subsoil is amplified with increasing train speeds, which may cause significant plastic strains in path-dependent subsoil materials.

Practical Numerical Model for Nonlinear Analyses of Wave Propagation and Soil-Structure Interaction in Infinite Poroelastic Media (무한 다공성 매질에서의 비선형 파전파 해석과 지반-구조물 상호작용 해석을 위한 실용적 수치 모형)

  • Lee, Jin Ho
    • Journal of the Earthquake Engineering Society of Korea
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    • v.22 no.7
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    • pp.379-390
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    • 2018
  • In this study, a numerical approach based on mid-point integrated finite elements and a viscous boundary is proposed for time-domain wave-propagation analyses in infinite poroelastic media. The proposed approach is accurate, efficient, and easy to implement in time-domain analyses. In the approach, an infinite domain is truncated at some distance. The truncated domain is represented by mid-point integrated finite elements with real element-lengths and a viscous boundary is attached to the end of the domain. Given that the dynamic behaviors of the proposed model can be expressed in terms of mass, damping, and stiffness matrices only, it can be implemented easily in the displacement-based finite-element formulation. No convolutional operations are required for time-domain calculations because the coefficient matrices are constant. The proposed numerical approach is applied to typical wave-propagation and soil-structure interaction problems. The model is verified to produce accurate and stable results. It is demonstrated that the numerical approach can be applied successfully to nonlinear soil-structure interaction problems.