• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.862-870
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• 2010

This thesis has been researched on optimized design method for the total cross section of embankment considering the fact that the size of embankment cross section is directly related with economic efficiency when dam designing. In general, embankment cross section of fill dam is either determined by cohesion and angle of internal friction, a strength parameter of embankment materials or by permeability of embankment. Therefore the size of embankment cross section depending on strength parameter of embankment materials was determined by using MIDAS-GTS program through stress-seepage coupled analysis at the time of fill dam design. As a result, determination of embankment cross section was more affected by the size of central core and permeability rather than by slope stability by shear strength and it was revealed that in case of embankment height being over 20m, stability against infiltration and slope action could be secured only when embankment slope is at least over 1:2.5. In addition, it was also revealed that in case of making the size of central core exceeding specification standard, total cross section of embankment could be reduced considerably and at the time of embankment design, adequate size and appropriateness of embankment cross section could be determined with referring the table suggested by this study.

• Geomechanics and Engineering
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• 제35권1호
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• pp.29-39
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• 2023

As the intensity of urban underground space development increases, more and more tunnels are planned and constructed, and sometimes it is inevitable to encounter situations where tunnels have to underpass the river embankments. Most previous studies involved tunnels passing river embankments perpendicularly or with large intersection angle. In this study, a project case where two EPB shield tunnels with 8.82 m diameter run parallelly underneath a river embankment was reported. The parallel length is 380 m and tunnel were mainly buried in the moderate / slightly weathered clastic rock layer. The field monitoring result was presented and discussed. Three-dimensional back-analysis were then carried out to gain a better understanding the interaction mechanisms between shield tunnel and embankment and further to predict the ultimate settlement of embankment due to twin-tunnel excavation. Parametrical studies considering effect of tunnel face pressure, tail grouting pressure and volume loss were also conducted. The measured embankment settlement after the single tunnel excavation was 4.53 mm ~ 7.43 mm. Neither new crack on the pavement or cavity under the roadbed was observed. It is found that the more degree of weathering of the rock around the tunnel, the greater the embankment settlement and wider the settlement trough. Besides, the latter tunnel excavation might cause larger deformation than the former tunnel excavation if the mobilized plastic zone overlapped. With given geometry and stratigraphic condition in this study, the safety or serviceability of the river embankment would hardly be affected since the ultimate settlement of the embankment after the twin-tunnel excavation is within the allowable limit. Reasonable tunnel face pressure and tail grouting pressure can to some extent suppress the settlement of the embankment. The recommended tunnel face pressure and tail grouting pressure are 300 kPa and 550 kPa in this study, respectively. However, the volume loss plays the crucial role in the tunnel-embankment interaction. Controlling and compensating the tunneling induced volume loss is the most effective measure for river embankment protection. Additionally, reinforcing the embankment with cement mixing pile in advance is an alternative option in case the predicted settlement exceeds allowable limit.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
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• pp.524-528
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• 2009

An influence factors for soundness evaluation of river levee include resistibility and embankment for piping of ground consisting embankment in case piping, permeability coefficient of ground, height of embankment, the width of crest, material characteristics of embankment and foundation ground, shape of embankment slope, an influence for penetration of rainfall or river water in case slope stability. In this study, it was operated a feasibility investigation of existing design result, stability evaluation for permeability coefficient use and permeability coefficient change of foundation ground to investigate an influence in line with permeability coefficient change for result of river levee penetration analysis. The evaluation results of influence factors, the permeability coefficient used in design and it was evaluated influence in safety factor of piping. After the evaluation of influence factors, the permeability coefficient used in the design appears with the fact that differs in a design report about same soil, Accordingly, the stability investigation of embankment by application of literature data can affect stability evaluation results by change factors like a permeability coefficient, void ratio. It should be certainly used material properties by a test in soundness evaluation of river levee.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.1519-1524
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• 2009

Construction of high-speed concrete track embankments over soft ground needs many of the ground improvement techniques. Drains, surcharge loading, and geosynthetic reinforcement, have all been used to solve the settlement and embankment stability issues associated with construction on soft soils. However, when time constraints are critical to the success of the project, another measures should be considered. Especially, since the design criteria of residual settlement is limited as 30mm for concrete track embankment, it is very difficult to satisfy this allowable settlement by using the former construction method. Pile net method consist of vertical columns that are designed to transfer the load of the embankment through the soft compressible soil layer to a firm foundation and one or more layers of geosynthetic reinforcement placed between the top of the columns and the bottom of the embankment. In this paper, three cases with different embankment height and number of geosynthetic reinforcement, were studied through FEM analysis for efficient use of pile net method.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.1036-1041
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• 2008

In order to analysis the reason of sliding failure in embankment slope under construction in soft soil area, a model section located in Gimhae Region in Gyeongsangnam-Do, where the sliding failure had been occurred during embankment works in soft soil area, had been selected. This area had been firstly treated with the Pack Drain Method, and additional embankment works of 9.7 meters out of total 14 meters in thickness had been under construction. The results of analysis showed that the reason of sliding failure were overspeed in embankment construction and the overestimation of design factors in calculating strength of each layer of embankment and poor management and inaccuracy reading of measurement devices.

• 한국지반공학회지:지반
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• 제5권4호
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• pp.17-26
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• 1989

토질제체 설계시 piping에 대한 대책으로 현재에 적용되고 있는 creep비는 원래 Masonry 또는 콘크리트 댐의 저면과 기초지반토질과의 접촉면에 따른 침투에 의한 piping의 방지를 위한 기준이었다. 본 연구에서는 이 creep비가 토질로 형성된 제체에서도 적용될 수 있는지의 여부를 모형실험을 통하여 구명하고 현행 creep비기준을 재평가 하였다. 연구결과 토질제체에서 발생되는 piping파괴는 토질제체와 기초지반과의 확측면에서는 발생하 지 않았으며 토질종류에 관계없이 제체내에서만 발생하였다. 따라서 제체를 형성하는 토질과 기초 지반토질중 투수계수가 적은 토질을 기준으로 creep비를 정하는 현재의 설계기준은 불합리함을 알 수 있었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.888-895
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• 2009

Compaction is a process of increasing soil density using physical energy. It is intended to improve the strength and stiffness of soil. In embankment, degree of compaction affects the construction time, money, also method of soil improvement. In large scale embankment project, difficulties of embankment should change due to uncertainty of settlement. So it is very important to predict the final settlement and factor of safety induced by embankment. In many construction site, there are primarily design of high embankment using in-situ soil. Therefore numerical analyses are necessary for valid evaluation of the settlement prediction. But due to the construction cost and schedule, there were lacking in properties of soil and also limited number of in-situ test were performed. So we proposed the method that can easily estimate the proper soil parameters and suggest the proper method of numerical analysis. From this, two-dimensional finite-difference numerical analysis was conducted to investigate the settlement and factor of safety induced by embankment with various case of compaction rate and embankment height.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1242-1247
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• 2007

An active application of concrete track is being expected for the future constructions of Korea railroad. For the successful construction and design in embankment section, the roadbed behavior should be reasonably estimated using the proper analysis method. In this research, behaviors of reinforced roadbed constructed with the determined stiffness and thickness at embankment section were estimated through various design parameters and numerical analysis. A three dimensional finite element method was employed to determine the proper reinforced roadbed thickness at embankment section. The displacement and vertical stress caused by train loading were estimated and compared with the field test results. The bearing characteristics of concrete track roadbed were presented. Moreover, the method to determine thickness of reinforced roadbed was proposed.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.1695-1704
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• 2008

The problems associated with constructing high-speed concrete track embankments over soft compressible soil has lead to the development and/or extensive use of many of the ground improvement techniques used today. Drains, surcharge loading, and geosynthetic reinforcement, have all been used to solve the settlement and embankment stability issues associated with construction on soft soils. However, when time constraints are critical to the success of the project, owners have resorted to another innovative approach. Especially, the design criteria of residual settlement is limited as 30mm for concrete track embankment, it is very difficult to satisfy this standard using the former construction method. Pile net method consist of vertical columns that are designed to transfer the load of the embankment through the soft compressible soil layer to a firm foundation and one or more layers of geosynthetic reinforcement placed between the top of the columns and the bottom of the embankment. This paper will present the guidelines for the design of pile net method to supported embankments. These guidelines were developed based on a review of current design methodologies and a parametric study of design variables using numerical modeling.

• 한국지반환경공학회 논문집
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• 제10권4호
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• pp.33-40
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• 2009

성토 시공시, 경제적인 시공을 위해 절 성토량의 균형은 중요하게 고려되어야 할 사항이다. 그러나 실제 완성기면까지 성토시 성토체 자체의 압축침하와 연약지반 성토시 발생하는 제체하부 원지반의 압밀침하, 암 버럭 사이의 간극 메움에 의한 침하와 강우와 유출시 발생하는 토량 손실에 의한 성토량의 부족분이 발생하고 있다. 성토량의 부족분에 대한 지침은 도로공사 시방서에 토량환산계수를 통해 설계하도록 되어 있지만 성토체 자체의 압축침하에 의한 부족분은 고려되고 있지 않다. 따라서 본 연구에서는 이세전(伊勢田)(1972)와 석정(石井)(1976)가 제안하고 있는 성토체의 제체압축침하량 산정기법을 적용하여 국내 여러 현장의 성토체를 대상으로 발생가능한 압축침하량을 산정하였다. 본 연구결과 성토고 및 성토재의 종류에 따라 성토고의 약 3~10%내외의 전침하량이 발생하는 것으로 나타났다. 그러므로 실제 설계시 성토재의 특성 및 성토고를 고려한 성토체의 즉시침하 및 크리프 침하를 반영한 설계가 필요할 것으로 판단된다.