• Title/Summary/Keyword: allowable settlement

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Settlement Problems in Shallow Foundations (얕은 기초에서의 침하문제)

  • 이상덕
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.11a
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    • pp.53-80
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    • 2002
  • Settlement in the Shallow Foundation are presented. Various practical methods to calculate immediate settlement, consolidation settlement, and secondary compression of the compressive soils under the shallow foundation are summerized. Especially the critical depth for settlement calculation, the contact pressure, the allowable settlement of the shallow foundation are recommended.

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Analysis of Load-Settlement Curves in Driven and Embedded Piles (항타 및 매입말뚝의 하중-침하량 곡선의 분석)

  • 천병식;조천환
    • Geotechnical Engineering
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    • v.13 no.6
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    • pp.61-70
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    • 1997
  • Although the load -settlement curve characteristics of embedded piles are different from those of driven piles, for the determination of their allowable loads the same analysis method has been adopted without any considerations. According to the related domestic chi teria, the analysis methods of load-settlement curve have some conflicts among themselves and have several vague points in obtaining the allowable capacity from ultimate or yield capacity. In order to solve those problems, the relevant literatures were reviewed. And also the result of 106 pile load tests was analysed. Analysis result indicates that analysis met hods of the load-settlement curve based on single mathematical curve are not suitable for the general analysis method of load-settlement curves due to their various characteristics. As a result, the appropriate analysis methods and safety factors for the determination of allowable capacity of pile are suggested in this paper.

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Settlement and Bearing Capacity of Roadbed Subjected to Tilting-train Loading in Various Ground Conditions

  • Jeon, Sang-Soo
    • International Journal of Railway
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    • v.8 no.2
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    • pp.35-41
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    • 2015
  • Tilting-train is very attractive to the railroad users in the world due to the advantage of high speed in curved track using pre-existing infrastructure of railway. Tilting-train has a unique allowable speed and mechanism especially in curved track. In this work, when tilting-train is operated with the allowable speed, the behavior of roadbed is evaluated by examining its settlement and bearing capacity. Additionally, the stability of roadbed is estimated as the roadbed is in the condition of soft soil influenced by the weather effects and cyclic train loading. Numerical results show that the roadbed settlement satisfies the allowable settlement when the elastic modulus of upper roadbed should be greater than $5000t/m^2$.

Analysis of Allowable Settlement on Tracks of High Speed Railway (고속철도 궤도 종류에 따른 허용침하량 분석)

  • Kim, Young-Ho;Jeong, Sang-Seom;Seol, Hoon-Il;Han, Young-Ah
    • Journal of the Korean Geotechnical Society
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    • v.24 no.11
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    • pp.25-34
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    • 2008
  • An application of concrete track is being actively processed for the construction of Korean high speed railway. The concrete track has an advantage in decreasing the maintenance cost, whereas it has much difficulty controlling the long term settlement after settlement occurred. Therefore, the management and control of settlement are very important for the successful construction of concrete track. The purpose of this paper is to verify the allowable settlement between concrete track and ballast track, and piled raft foundation installation effects as settlement reducers for concrete track. Therefore, a series of 3D finite element analyses that take into account the allowable settlement were performed for major parameters such as soil condition, pile installation and loading type. Based on the analysis, it is shown that concrete track causes much smaller settlement than ballast track, and the effect of installation is necessary to effectively reduce the settlement of concrete track.

Evaluation of the Structural Stability of Rammed Earth Construction :The Case Restoration Project of the Stone Pagoda at Mireuksa Temple Site in Iksan

  • Min, Hwang-Sik;Choen, Deuk-Youm
    • Architectural research
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    • v.20 no.3
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    • pp.65-73
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    • 2018
  • The restoration of foundations supporting the immense load of the stone pagoda at Mireuksa Temple Site prioritizes securing its structural stability. But so far, rammed earth construction is still not easy to determine the structural stability. This paper aims to emphasize that a scientific experimental study was conducted on a rammed earth construction, to identify its methodology and obtain objective data about structural stability of the foundation work. An experimental study fabricated specimens from the soil that had been removed during the excavation survey, determined the allowable bearing capacity through plate load tests, and compared the results with the predicted stress after reassembly of the stone pagoda to estimate the structural stability. Then, the repair method was selected based on the experimental study result. The evaluation method of the restoration of foundations consisted of an examination of the allowable bearing capacity and settlement. The allowable bearing of the reinforced foundation was more than twice the contact pressure under the stacked stones of the pagoda. The possibility of settlement of the rammed earth foundation soil layer during the pagoda assembly is expected to be very low because the settlement amount of the reformed soil layer is less than half of the settlement of the stabilized existing soil layer.

Study of Determination of Allowable Residual Settlement of Concrete Track Roadbed for High-Speed Railway (콘크리트궤도 토공노반의 허용잔류침하량 결정에 관한 연구)

  • Lee, Il-Wha;Yang, Shin-Chu;Jang, Seung-Yup
    • Proceedings of the KSR Conference
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    • 2007.11a
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    • pp.1121-1125
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    • 2007
  • An active application of concrete track is being expected for the future construction of Korean railroad. For the successful concrete track construction and design in earthwork areas, the residual settlement should be reasonably estimated using the proper method. The concrete track is extremely vulnerable to the damage of residual settlement. However, at the transition areas such as bridge approach, differential settlement will likely occur due to difference of stiffness, poor drainage and poor ground treatment. The maintenance is very difficult for excessive settlement on existing line, it is need to constrain the residual settlement in step of design. In this paper, it is performed the determination of the allowable residual settlement through various study to understand the residual settlement behavior of concrete track roadbed.

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Effect of Settlement Restoration Grouting between concrete track/Roadbed on the train service stability (콘크리트궤도 침하복원을 위한 궤도/노반 인터페이스부 그라우팅이 주행안정성에 미치는 영향)

  • Lee, Il-Wha;Lee, Sung-Jin;Lee, Tae-Guen;Kang, Tae-Ho
    • Proceedings of the KSR Conference
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    • 2008.11b
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    • pp.796-804
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    • 2008
  • Various design factors should be considered in order to apply the concrete slab track system on the soil/rock roadbed. One of the important factors is the settlement of roadbed. This settlement of concrete track should be supervised under the allowable settlement limit. If the settlement of roadbed under the concrete track exceed the allowable limit, the train serviceability will considerably come down and furthermore the fatal disaster may happen. Therefore, in this paper we introduced a digitalized grouting method as a settlement restoration method that can be suitably adopted to the concrete slab track. And we also evaluated the train service stability through the analysis of the track behavior according to the difference of the stiffness between the grouted part and the original roadbed.

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Estimation of the Roadbed Settlement and Bearing Capacity According to Radius of Curve and Cant in Railroad (철도의 곡선반경 및 캔트에 따른 노반의 침하 및 지지력 산정)

  • Jeon, Sang-Soo;Eum, Gi-Young;Kim, Jae-Min
    • Journal of the Korean Society of Hazard Mitigation
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    • v.7 no.1 s.24
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    • pp.29-38
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    • 2007
  • The research on the track performance and stability of the tilting-train was performed and the settlement of the roadbed was estimated as the tilting train was being operated on the rail joint under the allowable velocity subjected to the track performance and the stability of the tilting-train. Since the impact on the continuous welded rail (CWR) induced by the tilting-train loading is different from the impact on the rail joint, it needs to investigate the settlement of the roadbed beneath the CWR. In this study, when the tilting-train is being operated on the CWR under the allowable velocity subjected to the track performance and the stability of the tilting-train, the settlement and bearing capacity of the roadbed beneath the CWR have been evaluated using numerical analysis and compared with those beneath the rail joint. The numerical results show that the settlements of the roadbed beneath CWR and rail joint are amount to 71.2% and 88.8% of the allowable settlement, respectively. And the stresses are amount to 10.4% and 12.1% of the allowable bearing capacity, respectively.

PRCG Method to restore settled concrete track and structure (침하된 콘크리트궤도 및 구조물의 복원을 위한 PRCG공법)

  • Lee, Il-Wha;Lee, Sung-Jin;Lee, Su-Hyung;Kang, Tae-Ho;Shin, Hak-Yong
    • Proceedings of the KSR Conference
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    • 2010.06a
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    • pp.866-871
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    • 2010
  • Various design factors should be considered in order to apply the concrete slab track system on the soil/rock roadbed. One of the important factors is the settlement of roadbed. This settlement of concrete track should be supervised under the allowable settlement limit. If the settlement of roadbed under the concrete track exceed the allowable limit, the train serviceability will considerably come down and furthermore the fatal disaster may happen. Therefore, in this paper we introduced a PRCG(pressurized rapid-hardening cement grouting) method as a settlement restoration method that can be suitably adopted to the concrete slab track.

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