• Title, Summary, Keyword: Embankment and Foundation

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Settlement of Embankment and Foundation for Concrete Track of Gyungbu High Speed Railroad (경부고속철도 콘크리트궤도 토공 및 원지반 침하 (I))

  • Yang, Shin-Chu;Moon, Jae-Suk;Lee, Hyun-Jung;Kang, Dae-Woong;Kim, Dae-Sang
    • Journal of the Korean Society for Railway
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    • v.9 no.6
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    • pp.644-651
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    • 2006
  • An application of concrete track is being actively processed for the construction of Korean railroad. The concrete track has an advantage to decrease the maintenance ire, but is very difficult system to maintain after earthwork settlement occurred. Therefore, the management and control of embankment and foundation settlement is very important for the successful concrete track construction. We expect that the main part of the settlement of the concrete track is the one of embankment and foundation supporting it. Settlements vulnerable to the concrete track among the causes of lots of settlements are primary consolidation and secondary compression settlement of foundation, creep settlement of embankment, settlement caused by train load, and unequal settlement resulting from the difference of embankment material and construction process. This paper investigated the settlement causes to make badly effects on the concrete track and also evaluated the settlement with field tests and numerical analysis.

Evaluation of Foundation Settlement of Gyungbu High Speed Concrete Track Under Construction (건설 중인 경부고속철도 콘크리트궤도 기초침하 평가)

  • Kim, Dae-Sang;Yoo, Chung-Hyun;Kim, Hwan-Ki
    • Proceedings of the KSR Conference
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    • pp.365-370
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    • 2007
  • Foundation settlements(settlements at the embankment surface and ground) has been evaluating to satisfy the strict allowable residual settlement level from the start of the construction of Gyungbu high speed railway. This is because both embankment and ground settlement could be important to minimize the residual settlement after the construction of concrete track. Ground settlement is caused by the increase of effective stress resulting from embankment. The causes of embankment settlement could be come from different sources, for example, the increase of effective stress, rainfall, creep behaviors. Based on the field measured data, this paper analysed the settlement of ground and embankment settlement. The biggest settlement at the embankment surface was 9.7mm during 246days at the STA 000k922.5. The calculated settlement of embankment itself was 8.6mm at the same places. These results conclude that the compressive settlement of embankment could not negligible.

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Stability Analysis of the Reinforced Embankment on Soft Foundations using the Limit Equilibrium Method (한계평형법에 의한 연약지반 보강성토의 안정해석)

  • 고남영;고홍석
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.37 no.5
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    • pp.101-110
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    • 1995
  • The use of geotextile as reinforced materials in Soil structures has become widespread throughout the world. Geotextile reinforcement has been used in retaining walls, slope of embankment and especially soft foundation, etc. In the past, however, its design and construction have been performed empirically. In this study, to investigate of the effect of geotextiles reinforced slope of the embankment on a very soft foundation, a limit equilibrium analysis program calculating the safety factor of embankment on very soft foundation was developed. The study was focussed on such factors as type of geotextile, tensile strength, amount of reinforcement, and inclination of embankment. And the 4imit equilibrium analysis program was written on the basis of Low's slope stability theory with some modification. The following conclusions were drawn from this study. (1) The orientation of reinforcement can be assumed either horizontal or tangential to the slip circle. The factor of safety with tangential reinforcement is larger than that with the horizontal reinforcement. (2) In general, the factor of safety increases, as the slope reduces. However, it is preferable to use geotextiles with higher tensile strength rather than to reduce the slope of the embankment, because it is difficult to adjust the slope as desired. (3) The factor of safety obtained by numerical computation is affected only by the tensile strength, but not by the type of the geotextile.

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Applications of the Light Weight Method of EPS to Sub-road Fills at the Seaside (해안 도로상의 EPS 하중경감공법의 해석)

  • 장용채
    • Journal of Korean Port Research
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    • v.14 no.2
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    • pp.233-239
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    • 2000
  • The expansion of old road is needed in constructing the entrance at the $\bigcirc$$\bigcirc$I/C road in $\bigcirc$$\bigcirc$city. To strength the national competition, many agents who concerned do their best for finishing that construction early as soon as possible. In generally, soil embankment on soft foundation is caused to reduce the stability by making the settlement of ground surface due to the over load. Thus, we try to make it stable by building EPS embankment construction which in our working place is one kind of the method of light embankment construction after excavating the original ground.

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Permeability Influence of Base Soil for Analysis of Road Landfill Stability (도로성토사면의 안정성 분석시 원지반 투수성의 영향)

  • Kim, Young-Muk;Kim, Chung-Ki;Kim, Man-Goo;Kim, Geon-Hae
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.890-897
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    • 2005
  • Stability of embankment is influenced on landfill condition, permeability, shear strength and soil engineering propensity and so on, and need examination in reply because is different according to change of soil property of foundation ground and permeability condition. Analyzed seepage behaviour by finite element method for embankment, and change permeability of base to analyze effect that permeability of ground water table formation before embankment and analyze seepage behaviour to typical embankment in this research. In the case of permeability of foundation ground is 10 more than landfill permeability, rise of groundwater table was changed slightly. Pore water pressure was decreased slowly in landfill after rainfall. The effect of permeability of foundation ground was effected in change of pore water pressure. For permeability of foundation ground is 10 more than landfill, stability of road landfill was small changed during rainfall. But in the case of permeability of base soil similar to landfill permeability, road landfill stability was large decreased during rainfall.

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An Experimental Study on Piping Failure of Earth Embankment (토질제체의 Piping 파괴에 대한 실험적 연구)

  • Jeong, Hyeong-Sik;Ryu, Jae-Il;An, Sang-Ro
    • Geotechnical Engineering
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    • v.5 no.4
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    • pp.17-26
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    • 1989
  • The creep ratio, which has been applied as a measure to prevent piping failure in designing embankments, has been originally proposed for the protection of masonry or concrete dam from piping along the boundary surface between the foundation soil and the bottom of the structure. In this study, it has been investigated whether this creep ratio could be applied for the earth embankment through the model test and we reevaluated the required creep ratio in the present design criteria. Based on this research, it was concluded that a piping failure would always occur within the embankment body and not through the boundary surface between the embankment and foundation. Therefore it could be said that the present design criteria are illogical to determine the design creep ratio according to less permeable soil no matter whether the soil forms embankment or foundation.

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Lateral Earth Pressure Caused by Action on Earth Retaining Wall in Clay Foundation Ground with Consideration of Construction Speed (지중 구조물에 작용하는 측방토압에 대한 성토 재하 속도의 영향)

  • Im Eun-Sang;Lee Kang-Il
    • Journal of the Korean Geotechnical Society
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    • v.20 no.7
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    • pp.57-68
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    • 2004
  • When an embankment is constructed on soft clay ground, the lateral displacement generally called as lateral flow is generated in the foundation ground. It strongly affects stabilities of structures, such as foundation piles and underground pipes, in and on the foundation ground. The lateral earth pressure induced by the lateral flow is influenced by the magnitude and construction speed of embankment, the geometric conditions and geotechnical characteristics of the embankment, and the foundation ground, and so on. Accurate methods for estimating the lateral earth pressure have not ever been established because the lateral flow of a foundation ground shows very complicated behavior, which is caused by the interaction of shear deformation and volumetric deformation. In this paper, a series of model tests were carried out in order to clarify effects of construction speed of an embankment on the lateral earth pressure in a foundation ground were design. It was found that the magnitude and the distribution of the lateral earth pressure and its change with time are dependent on the construction speed of the embankment. It was found that a mechanism for the lateral earth pressure was generated by excess pore water pressure due to negative dilatancy induced by shear deformation under the different conditions of construction speeds of embankments.

Differential settlements in foundations under embankment load: Theoretical model and experimental verification

  • Wang, Changdan;Zhou, Shunhua;Wang, Binglong;Guo, Peijun;Su, Hui
    • Geomechanics and Engineering
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    • v.8 no.2
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    • pp.283-303
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    • 2015
  • To research and analyze the differential settlements of foundations specifically, site investigations of existing railways and metro were firstly carried out. Then, the centrifugal test was used to observe differential settlements in different position between foundations on the basis of investigation. The theoretical model was established according to the stress diffusion method and Fourier method to establish an analytical solution of embankment differential settlement between different foundations. Finally, theoretical values and experimental values were analyzed comparatively. The research results show that both in horizontal and vertical directions, evident differential settlement exists in a limited area on both sides of the vertical interface between different foundations. The foundation with larger elastic modulus can transfer more additional stress and cause relatively less settlement. Differential settlement value decreases as the distance to vertical interface decreases. In the vertical direction of foundation, mass differential settlement also exists on both sides of the vertical interface and foundation with larger elastic modulus can transfer more additional stress. With the increase of relative modulus of different foundations, foundation with lower elastic modulus has larger settlement. Meanwhile, differential settlement is more obvious. The main error sources in theoretical and experimental values include: (a) different load form; (b) foundation characteristics differences; (c) modulus conversion; (d) effect of soil internal friction.

A Study on Deformation of Soft Clay Foundation by Embankment Construction (제방축조에 의한 연약점토지반의 변형해석에 관한 연구)

  • 정형식;황영철
    • Geotechnical Engineering
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    • v.9 no.2
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    • pp.55-64
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    • 1993
  • When earth structures such as dykes or embankments are constructed on very soft clay foundation, unexpectedly large deformations of earth structures as well as clay foundation are encountered during and after construction. The final constructed section is composed of a portion of embankment above the existing ground level and that which penetrated into the soft foundation soil. This study is aimed to correctly estimate the shape of earth structures which penetrate some depth into the soft clay foundation. In this study the methods to predict penetration depth and deformation shape of embankment section after dumping of construction material. Model tests were carried out to prove the developed theory and FEM analysis. And when the mat is added, reinforcement effect was markedly noticed.

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Settlement of Embankment and Foundation for Concrete Track of Gyungbu High Speed Railroad (II) (경부고속철도 콘크리트궤도 토공 및 원지반 침하 (II))

  • Kim, Dae-Sang;Park, Seong-Yong;Shin, Min-Ho;Lee, Hyeon-Jung;Kim, Hyun-Ki
    • Journal of the Korean Society for Railway
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    • v.10 no.5
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    • pp.457-462
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    • 2007
  • An application of concrete track is being activity processed for the construction of Korean railroad. The concrete track has an advantage to decrease the maintenance fee, but is very difficult to control the settlement of ground and embankment consisting of substructure of concrete track below the allowable settlement level. This is the reason why the measurement and evaluation of both ground and embankment settlement before the installation of the concrete track is very important. One ground, a lower subgrade, and five surface settlements are measured to understand the settlement behavior of ground and embankment settlement. The period to measure settlements was more than 1 year after the completion of embankment. In this test site, ground settlement was over during the construction of embankment, but the embankment settlement are being continuously proceeded after the completion of embankment. The settlement velocity gradually is slowing down as time goes by. This paper also analysed the reasons of abrupt settlement increase and concluded that the rainfall was one of the important reason to increase settlement rate.