• Title/Summary/Keyword: Civil Movement

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유한 요소법을 이용한 중소하천 유역에서의 이동호우에 대한 유출특성 분석

  • Cho, Hyeon-Kyeong;Lee, Yeung-Hwa;Choi, Yun-Yeong
    • Journal of Environmental Science International
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    • v.7 no.4
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    • pp.415-424
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    • 1998
  • In the rainfalll-runoff relation, consideration of the spatial movement of storms is very unportant in designing a hydraulic structure or evaluating an environmental influence for land usage. Because of thins reason, this study has suggested the finite element model which consider the spatial movement of a storm and it was applied on a small river basin(Wi stream basin). In the application of the model, the basin was treated as a pivot point and the storms are simulated 10 movement in each directions. As a result, It shows that the storms moving from north to south have higher peak discharge and faster peak time than the storms moving in other directions. So these characteristics have to be considered In the designation of a hydraulic structure or evaluation of an environmental influence.

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Numerical investigation of floating breakwater movement using SPH method

  • Najafi-Jilani, A.;Rezaie-Mazyak, A.
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.3 no.2
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    • pp.122-125
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    • 2011
  • In this work, the movement pattern of a floating breakwater is numerically analyzed using Smoothed Particle Hydrodynamic (SPH) method as a Lagrangian scheme. At the seaside, the regular incident waves with varying height and period were considered as the dynamic free surface boundary conditions. The smooth and impermeable beach slope was defined as the bottom boundary condition. The effects of various boundary conditions such as incident wave characteristics, beach slope, and water depth on the movement of the floating body were studied. The numerical results are in good agreement with the available experimental data in the literature The results of the movement of the floating body were used to determine the transmitted wave height at the corresponding boundary conditions.

Tunnel Deformation in Shallow Unconsolidated Ground by Using Strain-Softening Model (변형연화모델을 이용한 미고결 지반의 터널변형)

  • Seo, In-Shik;Kim, Byung-Tak
    • Journal of the Korean Society of Industry Convergence
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    • v.10 no.2
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    • pp.81-88
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    • 2007
  • In case of an urban tunnel, the displacement of ground base controls the tunnel design because it is built on shallow and unconsolidated ground many times. There are more insufficiency to describe the ground movement which coincides in the measured result of the situ because the design of an urban tunnel is dependent on the method of numerical analysis used to the existing elastic and elasto-plastic models. We studied about the prediction for the ground movement of a shallow tunnel in unconsolidated ground, mechanism of collapse, and settlement. Also this paper shows comparison with the existing elastic and elasto-plastic model using the unlinear analysis of the strain-softening model. We can model the real ground movement as the increasement of ground surface inclination or occurrence of shear band by using strain-softening model for the result of ground movement of an urban NATM tunnel.

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Shrinkage movement analysis of reinforced concrete floors constructed in stages

  • Kwan, A.K.H.;Ng, P.L.
    • Computers and Concrete
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    • v.6 no.2
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    • pp.167-185
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    • 2009
  • Reinforced concrete floors constructed between movement restraints often crack seriously due to shrinkage after completion. One common mitigation measure is to construct the concrete floors in stages to allow part of the shrinkage movement to take place before completion. However, shrinkage movement analysis of concrete floors constructed in stages is quite cumbersome, as the structural configuration changes during construction, thus necessitating reanalysis of the partially completed structure at each stage. Herein, a finite element method for shrinkage movement analysis of concrete floors constructed in stages is developed. It analyses the whole structure, including the completed and uncompleted portions, at all stages. The same mesh is used all the time and therefore re-meshing and location matching are no longer necessary. This is achieved by giving negligibly small stiffness to the uncompleted portions, which in reality do not exist yet. In the analysis, the locked-in strains due to increase in elastic modulus as the concrete hardens and the creep of the hardened concrete are taken into account. Most important of all, this method would enable fully automatic shrinkage movement analysis for the purpose of construction control.

Viscous fluid characteristics of liquefied soils and behavior of pile subjected to flow of liquefied soils (액상화된 지반의 점성 유체 특성과 그 흐름이 말뚝의 거동에 미치는 영향 분석)

  • Hwang, Jae-Ik;Kim, Chang-Yeob;Chung, Choong-Ki;Kim, Myoung-Mo
    • Proceedings of the Korean Geotechical Society Conference
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    • 2004.03b
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    • pp.722-729
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    • 2004
  • The horizontal movement of sloping ground due to flow liquefaction has caused many pile foundations to fail, especially those in ports and harbor structures. In this study, a virtual case is assumed in which flow liquefaction is induced by earthquake loads in a fully saturated infinite sand slope with a single pile installation. Under the assumption that the movement of liquefied ground is viscous fluid flow, the influence of ground movement due to flow liquefaction on the pile behavior was analyzed. Since the liquefied soil is assumed as a viscous fluid, its viscosity must be evaluated, and the viscosity was estimated by the dropping ball method ,md the pulling bar method. Finally, the influence of the flow of liquefied soil on a single pile installed in an infinite slope was analyzed by a numerical method.

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First Results of GPS Measurements Along the Lai Chau - Dien Bien Fault in North-West Vietnam

  • DUONG Chi Cong;YUN Hong-Sic;CHO Jae-Myong;LEE Dong-Ha
    • Korean Journal of Geomatics
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    • v.5 no.1
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    • pp.51-58
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    • 2005
  • GPS measurements from Feb. 2002 through Mar. 2004 were used to estimate recent crustal movement across the Lai Chau - Dien Bien fault system in North-West Vietnam. Four GPS campaign data were processed and combined with appropriate constraints using automatic GAMIT/GLOBK run in order to estimate ITRF2000 coordinates, local horizontal velocity and extensive/compressive strain rates. ITRF2000 velocities are consistent with east-southeastward movement of Sundaland i.e. Indochina. Local velocities show not much left-lateral strike-slip of the fault system and derived strain rates are insignificant from zero at $95\%$ confidence.

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Static and dynamic responses of a tied-arch railway bridge under train load

  • Gou, Hongye;Yang, Biao;Guo, Wei;Bao, Yi
    • Structural Engineering and Mechanics
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    • v.71 no.1
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    • pp.13-22
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    • 2019
  • In this paper, the static and dynamic responses of a tied-arch railway bridge under train load were studied through field tests. The deflection and stresses of the bridge were measured in different static loading scenarios. The dynamic load test of the bridge was carried out under the excitation of running train at different speeds. The dynamic properties of the bridge were investigated in terms of the free vibration characteristics, dynamic coefficients, accelerations, displacements and derailment coefficients. The results indicate that the tie of the measuring point has a significant effect on the vertical movement of the test section. The dynamic responses of arch bridge are insensitive to the number of trains. The derailment coefficients of locomotive and carriage increase with the train speed and symmetrically distributed double-line loads reduce the train derailment probability.

Numerical Analysis of Utility Tunnel Movement under Reclamation Ground (매립지반 지하공동구의 수평이동원인에 대한 수치해석적 분석)

  • Yoon, Woo Hyun;Hwang, Chulsung
    • Journal of the Korean Society of Safety
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    • v.28 no.5
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    • pp.35-40
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    • 2013
  • Recently reclamation land is largely developed to utilize the land according to economic growth. The soil of landfill is soft, low shear strength, which makes it difficult to use the equipment. A large movement is occurred on the utility tunnel under construction. The inclined land with high water level and underground facilities are widely distributed and the excess pore water pressure may occur under construction similarly to this study. Some different conditions are made to design result, such as 4m of soil piling near the construction area, heavy rainfall during 2nd excavation that may cause flow liquefaction. To analyze the cause of transverse lateral movement, Three dimensional analysis are performed to four load cases, which is original design condition, flow liquefaction by heavy rainfall, unsymmetric lateral soil pressure, and both of them simultaneously. Ten steps of full construction stage, 1st excavation for utility tunnel, construction of utility tunnel, 1st refill, piling soil from 1m to 4 m, 2nd excavation for drainage culvert, liquefaction around the utility tunnel, construction of drainage culvert and 2nd refill, are take into account to investigate the cause of movement.

A Study on the Sediment Movement Using Numerical Models (수치모형을 이용한 하상변동 연구)

  • Im, Chang-Su;Son, Gwang-Ik;Lee, Jae-Jun;Yun, Se-Ui
    • Journal of Korea Water Resources Association
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    • v.32 no.2
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    • pp.131-142
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    • 1999
  • In this study, one and semi-two dimensional numerical models were applied to study on the hydraulic and sedimentologic characteristics of upstream and downstream channel section near the Buyeo intake towers. The HEC-6 model was applied for the simulation of one dimensional sediment movement from 1988 to 1996, and GSTARS model was applied for the simulation of semi-two dimensional sediment movement for the same period. After the verification of accuracy of HEC-6 and GSTARS models, the models were applied again to predict the sediment movement near intake towers from 1988 to 2001. In this case, measured channel section of 1988 was used as an initial channel condition, and used to predict the long-term variation of channel section of 2001 after 13 years since 1988. The simulation results show that the channel bed is sedimented and eroded repeatedly in the main channel of overall study area, and that channel bed is getting elevated in the near Buyeo intake towers.

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The Study of Group Piles under Lateral Soil Movement in Sand by Model test (모래지반에서 측방변형을 받는 무리말뚝의 실험적 연구)

  • Bae, Jong-Soon;Kim, Sung-Ho;Kwon, Min-Jea
    • Journal of the Korean Geotechnical Society
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    • v.22 no.10
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    • pp.165-172
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    • 2006
  • This study describes a series of model tests on instrumented pile groups embedded in HAP-CHEN sand undergoing lateral movement. We tried to find the effect of group piles dependent on a number of factors, including the position of the pile in a group, the pile spacing, and the pile arrangement. The results of test are as follows. For the group piles, the bending moment profile for each pile is similar in shape to that of single pile, although the magnitude and the position of the maximum bending moment are different. $R_M$ (the ratio of maximum bending moment) and $R_F$ (the ratio of resistance to lateral soil movement) were found to increase with increasing pile spacing. When a pile is in a group under lateral soil movement, RM increased in the order of the middle row, front row, back row, according to the direction of lateral deformation, and the outer pile has a larger RM than the inner pile.