• Title/Summary/Keyword: transiton zone

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Characteristics of Track and Train Behaviors on High-Speed Railway Bridge/Earthwork Transiton Zone (고속철도 교량/토공 접속부에서의 궤도 및 차량 거동 특성)

  • Lee, Il-Wha;Kang, Yun-Suk;Kim, Eun;Son, Ki-Jun;Park, Chan-Kyoung
    • Proceedings of the KSR Conference
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    • 2003.10b
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    • pp.129-134
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    • 2003
  • It is very important to pay careful attention to construction of bridge/earthwork transition zone for high-speed railway. The transition zone of the railway is the section which roadbed stiffness is suddenly varied. Differences in stiffness have dynamic effects and these increase the forces in the track and the extent of deformation. An abrupt change of stiffness across two adjacent track portions cause irregular settlement of roadbed, track irregularity, lack of girder bending moment and reduction of lateral resistance. Especially on high-speed railway, track irregularity of transition zone cause sincere effect to track stability and train safety. And so continuous maintenance is needed. To verify this effect and to improve transiton zone capacity, In situ test, track irregularity and train acceleration test were performed on high-speed railway bridge/earthwork Transiton Zone.

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Strain Distribution of transition zone in a nailed wall (네일로 보강된 구조물에서의 변이영역과 변형률 분포)

  • 장기태;남궁한;유병선;김경태;권병근;이선경
    • Proceedings of the Korean Geotechical Society Conference
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    • 2000.11b
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    • pp.235-239
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    • 2000
  • For the calculation of internal stability, the hypothesis in conventional design is on the basis of two distinct zones, which are 'active zone' and 'passive zone'. This means that there is an abrupt discontinuous transition from active to passive states across a potential failure line. The existence of a discontinuity of this nature appears physically unreasonable, especially from kinematic considerations. A series of pull-out model tests was undertaken from a wall being rotated about the toe to find the strain distribution mobilized from near the wall face into the deep, stable zone through the centre plane. With this finding of transition zone, the objective of study is aiming at identifying the likely effect of this zone in designing method by comparing with the prevailing design method.

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Strain Distribution of Transition Zone in a Nail Wall (네일로 보강된 구조물에서의 변이영역과 변형률 분포)

  • Chang, Ki-Tae;NamGung, Han;Yoo, Byung-Sun
    • Journal of the Korean Geophysical Society
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    • v.8 no.1
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    • pp.39-43
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    • 2005
  • For the calculation of internal stability, the hypothesis in conventional design is on the basis of two distinct zones, which are 'active zone' and 'passive zone'. This means that there is an abrupt discontinuous transition from active to passive states across a potential failure line. The existence of a discontinuity of this nature appears physically unreasonable, especially from kinematic considerations. A series of pull-out model tests was undertaken from a wall being rotated about the toe to find the strain istribution mobilized from near the wall face into the deep, stable zone through the centre plane. With this finding of transition zone, the objective of study is aiming at identifying the likely effect of this zone in designing method by comparing with the prevailing design method.

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Effects of Hydraulic Variables on the Formation of Freshwater-Saltwater Transition Zones in Aquifers

  • Park, Nam-sik
    • Korean Journal of Hydrosciences
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    • v.7
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    • pp.1-8
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    • 1996
  • The location and the shape of a freshwater transition zone in a coastal aquifer are affected by many hydraulic variables. To data most works to determine the effects of these variables are limited to qualitative comparison of transiton zones. In this work characteristics of transition zones are analyzed quantitatively. The investigation is limited to a steady-state transition zones. Three dimensionless variables are defined to represent characteristics of steady-state transition zones. They are maximum introsion length, thickness, and degree of stratification. Effects of principal hydraulic variables (velocity and dispersivity) on these characteristics are studied using a numerical model. Dimensional analysis is used to systematically analyze entire model results. Effects of velocity and dispersivity are seem clearly. From this study, increase in velocity is found to cause shrinkage of transition zones. This observation contradicts claims by some that, because dispersion is proportional to velocity, increase in velocity would cause expansion of transition zones.

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