• 한국농공학회지
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• 제37권5호
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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.

• 한국안전학회지
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• 제15권1호
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• pp.146-152
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• 2000

To estimate the behavior of reinforced and unreinforced embankment constructed on a impermeable foundation ground, a laboratory model test was performed for two types of soils and water level increasing velocity of a flood period. The experiment models were constructed with slopes of water level is 1.25cm/min, 2.5cm/min each. From model test results, as the slope of reinforced and unreinforced embankment was the slower, the more seepage line rised. In the unreinforced embankment, the rising velocity of water level was the faster, the larger the embankment failure was. And the reinforced embankment with geotextile was the more safe than the unreinforced embankment for seepage force.

• 한국지반환경공학회 논문집
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• 제2권2호
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• pp.51-58
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• 2001

본 연구에서는 보강제체와 무보강제체의 침투거동을 평가하기 위하여 실내모형실험을 실시하였다. 제체침투시험은 사면경사가 1:1.5, 1:2.0이고 수위상승속도가 1.25cm/min, 2.5cm/min, 수위는 15cm, 25cm, 35cm인 조건에서 실시하였다. 모형실험결과 보강재를 사용한 제체의 경우 지하수의 흐름과 상승 때문에 어느 정도의 침하와 수평방향변위가 발생하였으나, 무보강제체에서 나타난 커다란 활동파괴는 발생되지 않았다. 그리고 수위상승속도 변화에 따른 제체의 침투거동분석결과 Geotextile로 보강된 제체가 무보강제체보다 최종침하량이 감소하는 것으로 나타나 Geotextile을 설치한 제체가 비교적 물의 침투력에 대해 안정한 것으로 나타났다.

• 한국지반환경공학회 논문집
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• 제2권4호
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• pp.39-50
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• 2001

본 연구에서는 지오그리드로 보강된 도로제방 사면에 대해 한계평형해석에 근거한 보강사면해석 프로그램인 RSS를 이용하여 보강길이와 간격의 변화에 따른 사면의 안전율 변화를 살펴보았다. 해석결과 비보강시 기준안전율을 만족하지 못하는 사면에서 보강재길이의 증가에 따라 비보강사면에 비해 최대 50~150%의 안전율이 증가되었으며 보강길이를 증가시켜도 안전율의 추가상승이 없는 한계길이를 확인하였다. 또한 동일 가상보강단면에 대하여 범용프로그램인 FLAC을 이용하여 유한차분해석을 실시하여 안정성이 확보된 사면에 발생하는 수평변위, 수평응력, 보강재의 인장력을 산출하여 보강길이의 추가적인 증가에 의한 효과를 알아보았다. 해석결과, 파괴형태는 선단파괴 또는 사면내 파괴로 나타났으며 안정성을 확보한 상태에서는 한계평형해석결과와 동일하게 보강길이의 추가적인 증가에 의한 안정성 증대효과는 미미한 것으로 나타났다.

• Smart Structures and Systems
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• 제31권5호
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• pp.517-529
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• 2023

Using a device composed of two lateral pressure plates (LPPs) and a steel reinforcement bar to apply horizontal pressure on slope surfaces, a newly developed prestress-reinforced embankment (PRE) is proposed, to which can be adopted in strengthening railway subgrades. In this study, an analytical model, which is available of calculating additional confining stress (σ_H) at any point in a PRE, was established based on the theory of elasticity. In addition, to verify the proposed analytical model, three dimensional (3D) finite element analyses were conducted and the feasibility in application was also identified and discussed. In order to study the performance of the PRE, the propagation of σ_H in a PRE was analyzed and discussed based on the analytical model. For the aim of convenience in application, calculation charts were developed in terms of three dimensionless parameters, and they can be used to accurately and efficiently predict the σ_H in a PRE regardless of the embankment slope ratio and LPP side length ratio. Finally, the potential applications of the proposed analytical model were discussed.

• Geomechanics and Engineering
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• 제5권4호
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• pp.313-329
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• 2013

Vetiver grass (Vetiveria zizanioides) is being effectively used in many countries to protect embankment and slopes for their characteristics of having long and strong roots. In this paper, in-situ shear tests of the ground with the vetiver roots have been conducted to investigate the stabilization properties corresponding to the embankment slopes. Numerical analyses have also been performed with the finite element method using elastoplastic subloading $t_{ij}$ model, which can simulate typical soil behavior. It is revealed from field tests that the shear strength of vetiver rooted soil matrix is higher than that of the unreinforced soil. The reinforced soil with vetiver root also shows ductile behavior. The numerical analyses capture well the results of the in-situ shear tests. Effectiveness of vetiver root in geotechnical structures-strip foundation and embankment slope has been evaluated by finite element analyses. It is found that the reinforcement with vetiver root enhances the bearing capacities of the grounds and stabilizes the embankment slopes.

• 한국지반환경공학회 논문집
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• 제2권2호
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• pp.41-50
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• 2001

본 연구에서는 수위상승, 호안구조물의 증고 및 배면 준설투기 등 외적조건에 따른 ${\bigcirc}{\bigcirc}$항 호안구조물의 활동 및 측방유동에 대한 안정성 검토를 실시하고 기초보강 방안을 제시하였다. 안정성 검토를 위해 지반조사, 기본물성시험, 역학실험 및 화학성분분석을 실시하였고, 지반물성치는 주상개량체의 경우 지반개량 개념을 적용하였으며, 구조물 배면 준설매립의 경우는 단계별매립에 의한 영향을 고려하여 결정하였다. 안정성 검토는 기시공된 상태로 증고하지 않고 매립하였을 경우와 기시공된 상태로 증고하여 매립하였을 경우로 구분하여 실시하였다. 해석 결과 두가지 경우 모두 활동과 측방유동에 대해 불안정한 것으로 판단되어 기시공공법과 동일한 방법인 심층몰탈파일에 의한 추가보강을 실시할 경우에 대하여 그 안정성을 검토한 결과 안정하였다. 따라서 본 현장에 대한 기초보강공법으로써 심층몰탈파일을 제시하였다.

• 농업과학연구
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• 제39권1호
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• pp.97-110
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• 2012

This study was carried out for safety evaluation, the practical application and improvement of design method of the agricultural reservoir embankment according to backside extension. Seepage analysis, slope stability analysis and finite element analysis were performed for steady state and transient conditions. Also, the pore water pressure, seepage quantity, safety factor and stress-strain behavior according to high water level and rapid drawdown were compared and analyzed. The pore water pressure at contact region between backside extension and old embankment was kept high after rapid drawdown. Therefore, backside extension is recommended that design method is required to be improved and reinforced more than the others raising embankment. The hydraulic gradients before and after backside extension showed high value at the base of the core, but they showed stable state at the upstream slope and downstream slope. The seepage quantity per 1 day and the leakage per 100 m for the steady state and transient conditions appeared to be safe against the piping. The safety factor of slope stability showed high at the steady state, and transient conditions did not show differences depending on the rapid drawdown. The safety factor was appeared high at the upstream slope before backside extension and downstream slope after extension. The excess pore water pressure for steady state and transient conditions showed negative(-) at the upstream slope, it was small at the downstream slope. The mean effective stress (p') showed high at the base of the core and to be wild distribution after the extension. The displacement after extension showed 0.02-0.06 m in the upstream slope, the maximum shear strain after extension was smaller than that before extension.

• Geomechanics and Engineering
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• 제36권2호
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• pp.157-166
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• 2024

Generally, the rubble mound installed on the slope embankment of the open-type wharf is designed based on the impact of wave force, with no consideration for the impact of seismic force. Therefore, in this study, dynamic centrifuge model test results were analyzed to examine the acceleration amplification of embankment reinforced with rubble mound under seismic conditions. The experimental results show that when rubble mounds were installed on the ground surface of the embankment, acceleration response of embankment decreased by approximately 22%, and imbalance in ground settlement decreased significantly from eight to two times. Furthermore, based on the experimental results, one-dimensional site response (1DSR) analyses were conducted. The analysis results indicated that reinforcing the embankment with rubble mound can decrease the peak ground acceleration (PGA) and short period response (below 0.6 seconds) of the ground surface by approximately 28%. However, no significant impact on the long period response (above 0.6 seconds) was observed. Additionally, in ground with lower relative density, a significant decrease in response and wide range of reduced periods were observed. Considering that the reduced short period range corresponds to the critical periods in the design response spectrum, reinforcing the loose ground with rubble mound can effectively decrease the acceleration response of the ground surface.

• 한국농공학회논문집
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• 제58권2호
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• pp.31-44
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• 2016

This study analyzed pore water pressure, earth pressure and settlement through field monitoring on the project site in which raising embankments are being built through backside extension, and compared the behaviors of seepage analysis, slope stability analysis and stress-strain during flood water levels and rapid drawdown under steady state and transient condition. The variation of pore water pressure showed an increase during the later period in both upstream and downstream slope, with downstream slope more largely increased than upstream slope overall. The variation of earth pressure increased according to the increase of embankment heights, while the change largely showed in the upstream slope, it was slowly increased in the downstream slope. The settlements largely increased until 23 m as embankment heights increased, and showed very little settlement overall. Under a steady state and transient conditions, the seepage quantity per day and leakage quantity per 100 m of embankment against total storage were shown to be stable for piping. The hydraulic gradient at the core before and after raising embankments was greater than the limit hydraulic gradient, showing instability for piping. The safety factor of upstream and downstream slopes were shown to be very large at a steady state, while the upstream slopes greatly decreased at a transit conditions, downstream slopes did not show any significant changes. The horizontal settlements, the maximum shear strain and stress are especially distributed at the connecting portion of the existing reservoir and the new extension of backside. Accordingly, the backside extension method should be designed and reinforced differently from the cases of other types reservoirs.