• Journal of the Korean Society for Railway
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• 제12권2호
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• pp.276-284
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• 2009

Recently pile-supported embankments have emerged as an optimum method when the rapid construction and strict deformation of structures are required on soft soils. Especially geosynthetic-reinforced and pile-supported (GRPS) embankments are used worldwide as they can provide economic and effective solutions. However the load transfer mechanism in GRPS embankments is very complex, and not yet fully understood. Particularly the purpose and effect of geosynthetic inclusion are ambiguous and considered as an auxiliary measure assisting the arching effect of piles. Numerical parametric study using 3D finite element method has been conducted to investigate the effect of geosynthetic reinforcement on the load transfer mechanism of GRPS embankments. Numerical results suggested that as more stiffer geosynthetic is included, arching effect decreases considerably and the load concentration to the piles mostly caused by tension effect of geosynthetic. This finding is contradictory to the common understanding that geosynthetic inclusion only enhance the efficiency of load transfer. Consequently the design parameters determined from the numerical analyses are compared with those of three existing design methods. The problems of the existing methods are discussed.

• Journal of the Korean Geosynthetics Society
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• 제9권3호
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• pp.9-18
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• 2010

A series of model tests were performed to investigate the load transfer by soil arching in geosynthetic-reinforced and pile-supported(GRPS) embankment systems. In the model tests, model piles with isolated cap were inserted in the model container and geosynthetics was laid on the pile caps below sand fills. The settlement of soft ground was simulated by rubber form. The loads acting on pile caps and the tensile strain of geosynthetics were monitored by data logging system. At the given interval ratio of pile caps, the efficiency in GRPS embankment systems increased with increasing the height of embankment fills, then gradually converged at constant value. Also, at the given height of embankment fills, the efficiency decreased with increasing the pile spacing. The embankment loads transferred on pile cap by soil arching increased when the geosynthetics installed with piles. This illustrated that reinforcing with the geosynthetics have a good effect to restraint the movement of surrounding soft grounds. The load transfer in GRPS embankment systems was affected by the interval ratio, height of fills, properties of grounds and tensile stiffness and so on.

• Journal of the Korean GEO-environmental Society
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• 제9권2호
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• pp.67-74
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• 2008

Many industrialized countries of the world have many problems about the reuse of waste landfill area because of the increase of terminated waste disposal landfill. Especially, the effective use of the terminated waste disposal landfill nearby the urban area has been demanded, because of the lack of the usable land. However, in case of the construction of the building on such a landfill, ground settlement and reduced bearing capacity would be occurred without ground stabilization and proper reinforcement. This study is to evaluate the applicability of geosynthetics for the increment of bearing capacity of solid waste landfill ground. A numerical simulation has been undertaken to model a layer of weathered soil overlaying a layer of geosynthetic reinforcement and waste disposal ground. The proposed analytical model can be used to obtain surface settlement characteristic in the two-dimensional deformation related reinforcement.

• KSCE Journal of Civil and Environmental Engineering Research
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• 제28권2C호
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• pp.133-141
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• 2008

Theoretical analysis are developed to estimate the load transfer by soil arching in geosynthetic-reinforced and pile-supported(GRPS) embankment systems. According to the results of analyses, the efficiency of embankment pile systems increases when the geosynthetics are installed with piles. Especially the increment of efficiency is more remarkable in the low embankment height, where soil arching can not be fully developed. The factors affecting the load transfer in GRPS embankment systems are the pile spacing, the height and properties of embankments, and the strength of geosynthetics. The efficiency decreases with increasing the pile spacing, while it increases with the height and internal friction angle of embankment fills, and the strength of geosynthetics. These results of analyses show the proposed analysis method is resonable to estimate the soil arching in GRPS embankment systems.

• Journal of the Korean Geosynthetics Society
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• 제2권1호
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• pp.3-13
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• 2003

Recently, construction of the reinforced earth structures, which adopts reinforcing materials of geosynthetic, is rapidly increasing due to its good economic advantages, beautiful appearance, and convenient construction. Nonetheless, the most important factor of interpretation and design of the reinforced earth structures, which is assessment ways of friction features between earth and geosynthetic, has not been standardized yet. It has great difference of interpretation and design methods which suggested to the design engineer. This study is to present the way how to assess more reasonably friction features between geogrid and weathered granite soil through the pullout test. Based on a large-scale pullout test of geogrid, the maximum shear stress, interface fricton angle, and friction efficiency are presented with consideration of various test condition.

• Proceedings of the Korean Fiber Society Conference
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• 한국섬유공학회 1998년도 가을 학술발표회논문집
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• pp.348-351
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• 1998

토목 및 건설용으로 사용되는 토목섬유 중 지오그리드는 경사와 위사 방향으로 10~100mm 크기의 aperture가 형성된 격자 구조를 갖는 것을 지칭하며 1980년대에 개발되어 토목공사에 적용되어 왔으며, 강도가 요구되는 방향으로 높은 인장강도를 지님으로써 도로의 기초 지반과 포장층의 보강, 제방과 사면의 보강 및 보강토 옹벽공사용 둥에 사용되고 있다. (중략)

• Journal of the Korean Geotechnical Society
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• 제32권12호
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• pp.79-91
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• 2016

Geosynthetic-reinforced and Pile-supported (GRPS) embankment method is widely used to construct structures on soft ground due to restraining residual settlement and their rapid construction. However, effect of cyclic loading has not been established although some countries suggest design methods through many studies. In this paper, cyclic loading tests were conducted to analyze dynamic load transfer characteristics of pile-supported embankment reinforced with geosynthetics. A series of 3 case full scale model tests which were non-reinforced, one-layer-reinforced, two-layer reinforced with geosynthetics were performed on piled embankments. In these series of tests, the height of embankment and pile spacing were selected according to EBGEO (2010) standard in Germany. As a result of the vertical load parts on the pile and on the geosynthetic reinforcement measured separately, cyclic loads transferred by only arching effect decreased with strength geosynthetic-reinforced case. However, final loads on the pile showed no differences among the cases. These results conflict with previous studies that reinforcement with geosynthetics increases transfer load concentrated on piles. In addition, it is observed that the load transferred to pile decreases at the beginning of cycle number due to reduction of arching effected by cyclic loading. Based on these results, transferred mechanism for cyclic load on GRPS system has been presented.

• Journal of the Korean Geosynthetics Society
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• 제3권4호
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• pp.41-48
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• 2004

Recently a method for increasing the bearing capacity by laying the reinforcing materials with three or four layers as a method reinforcing the ground was studied recently. The purpose of this study is to examine the method for increasing shear-strength factor of the ground by reinforcing the ground under the foundation. According a method of wrapping ground with bakk-shape or semicircle-shape by geotextile was developed in this study and it looks likes anaspect that spreading footing exits under spread footing. A simulation loading-test using Aluminum sticks was carried out in order to examine the mechanism about bearing capacity of spread footing reinforced by geotextile. Increase of ultimate bearing capacity was verified in this simulation loading-test when charging loads to spread footing, which is propose from this study, reinforced by geotextile. And moving directions of points of the ground were also checked by grid-type indication method, and the areas where plastic failure appeared were checked by B-shutter photographing.

• Proceedings of the Korean Fiber Society Conference
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• 한국섬유공학회 2003년도 봄 학술발표회 논문집
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• pp.267-270
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• 2003

일반적으로 토목 공사에서 구조의 보강 용도로 주로 사용되는 지오그리드(geogrids)는 우수한 인장 탄성계수와 인장강력을 지니고 있어서 하중이 집중적으로 작용하는 토목 구조물에서 보강기능을 원활히 수행하는 보강재료 이지만, 비교적 큰 격자상 외관 구조를 가지므로 지오그리드를 관통하는 각종 물질, 특히 함유 수분과 세립질 토양의 이동이나 유실 등을 효과적으로 제어하지 못한다는 단점도 있어 사용상의 제약이 있다. (중략)

• Journal of the Korean Geotechnical Society
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• 제21권6호
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• pp.53-65
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• 2005

This paper presented a mechanism of the soil structure reinforced by geosynthetics, in which the reinforcing mechanism is treated as the effect arising from the reinforcement process to prevent the dilative deformation of soil under shearing. A full-scale in-situ model test was carried out by introducing the prestress method to enhance the geosynthetic-reinforcement, and the prestress effect through the FEM is also examined. The elasto-plastic model and the initial parameters needed in the FEM are presented. Moreover, the theoretical prediction is compared with the experimental results, which were obtained by a full-scale in-situ model test.