• Title, Summary, Keyword: 토공 및 원지반

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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.

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.

Behavior Characteristics of Precast Concrete-Panel Retaining Wall Adhered to In-situ Ground through Large Scaled Load Test (대형재하시험을 통한 원지반 부착식 패널옹벽의 거동특성)

  • Shin, Yuncheol;Min, Kyongnam;Kim, Jinhee;Ahn, Taebong
    • Journal of the Korean GEO-environmental Society
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    • v.17 no.11
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    • pp.45-53
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    • 2016
  • A precast panel wall system resists against the horizontal earth pressure by increasing the shear strength of ground by reinforcement connected to the panel. The application of precast panel wall system is growing to lately minimize the earth work and environmental damage caused by large cut slope and to use the limited land effectively. The ground adhered panel wall system is the construction method that has the panel engraved with natural rock shape to improve the landscape. This system is developed to complete Top-Down method, and it is possible to have vertical cut, and to adhere to in-situ ground, improve construction ability by minimizing the ground relaxation and exclusion the trench and backfill process. In this study the field tests were performed to verify the construction ability about the vertical cut and complete Top-Down process and the construction behavior of ground adhered panel wall system was analyzed by large scale loading test and measurement results during loading test.

Fundamental Study on Earthwork Quality Control Based on Intelligent Compaction Technology (지능형 다짐기술을 통한 토공사 품질관리를 위한 기초 연구)

  • Baek, Sung-Ha;Kim, Jin-Young;Cho, Jin-Woo;Kim, Namgyu;Jeong, Yeong-Hoon;Choi, Changho
    • Journal of the Korean Geotechnical Society
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    • v.36 no.12
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    • pp.45-56
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    • 2020
  • In this paper, intelligent compaction (IC) technology and the earthwork quality control specifications based on IC were analyzed, and the field study was conducted to investigate the relationship between the representative IC value CMV (Compaction Meter Value) and spot test results (plate bearing test and field density test). As the number of roller passes increased, both the CMV and spot test results increased. However, point-by-point comparison between CMV and spot test results yielded poor quality correlations; this is because the ununiform stiffness of the underlying layer and the moisture content of the lift layer affected the CMV and spot test results, respectively. Most international specifications related to IC requires knowledge of the IC values and their relationships with the soil properties obtained by the traditional spot tests. Therefore, for the successful implementation of intelligent compaction technology into earthwork construction practice, the number of roller passes as well as the lift thickness and the moisture content of the soil should be carefully considered.

A Estimation of Soil Conversion Factor Using Digital Photogrammetry and 3D Laser Scanner (디지털사진측량 및 3D 레이저스캐너를 이용한 토랑환산계수의 산정)

  • Lee Jae-Kee;Jung Sung-Heuk;Lee Kye-Dong
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.24 no.2
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    • pp.227-234
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    • 2006
  • Ministry of construction & transportation is operating for the soil and rock information system and is considered to accurate application of soil conversion factor that is essentially necessary for accurate calculation of earth volume. Since the balance of cutting earth in public work, the plan of spoil bank or borrow pit are directly related to construction costs, accurate calculation of earth volume and efficient scheme of haul are important. As such, this study has provided methods that can acquire information that is more rapid, applicable to job sites, and trustworthy by comparing resultant values of photogrammetry, laser scanning, or inside job site experimentations, and calculated soil conversion factor by applying photogrammetry and laser scanning methods for hard rock that has difficulty in calculating soil conversion factor. The study can provide alternatives that can resolve the problems of unbalanced earth volume that may arise in applying to plans the earth conversion factor that relies on planning books and experience without considering the characteristics of job site earth, and can establish its relevancy by calculating soil conversion factor for hard rock that has relative difficulties in doing inside or job site testing.

Evaluation of Field Application of Precast Concrete-panel Retaining Wall attached to In-Situ Ground Using Field Test and Numerical Analysis (현장시험 및 수치해석 분석을 통한 원지반 부착식 판넬옹벽의 현장 적용성 평가)

  • Kwon, Yong Kyu;Min, Kyoung-nam;Hwang, Young-cheol;Ban, Hoki;Lee, Minjae
    • Journal of the Korean Geotechnical Society
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    • v.36 no.12
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    • pp.99-106
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    • 2020
  • Man-made slope is inevitable to make a new road, which may result in environmental problems as well as collapse of slope. To prevent these problems, various methods such as geogrid reinforced retaining wall, precast concrete-panel retaining wall, and so on, have been introduced and developed. Among these methods, this paper presents the evaluation of field application of precast concrete-panel retaining wall attached to in-situ ground (so called top-down) compared to the conventional construction method of precast concrete-panel retaining wall (so called bottom-up) through the field test and numerical analysis. As a result, the safety factor of both methods in final stage is similar, however, top-down method guarantees the slope stability during the construction compared to bottom-up method.

Material and Behavior Characteristics of Lightweight Embankment for Road Constructed on Soft Ground (연약지반에 시공된 도로용 경량성토체의 재료 및 거동특성)

  • Yea, Geu-Guwen;Lee, Yong-Jae;Kim, Hong-Yeon;Yoon, Gil-Lim;Han, Sang-Hyun
    • Journal of the Korean Geosynthetics Society
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    • v.17 no.2
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    • pp.41-49
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    • 2018
  • The purpose of this study is to fabricate a full scale road embankment using lightweight air foamed soil as a soil material on soft ground and to investigate its material characteristics and behavior in order to promote dredged soil utilization and minimize ground improvement. As a result of the laboratory test of the onsite mixed samples, the total unit weight of the specimens decreased almost linearly until curing 28 days. In particular, the total unit weight after 28 days of curing was reduced to about 81% of the slurry state before curing, which will be useful in the formulation of similar native soil materials in the future. The unconfined compressive strength began to decrease with the 14th day of curing as shown in the previous study. When the cement content is increased, the strength decreases sharply at a small strain change after the occurrence of the maximum compressive strength, and the maximum strength is exhibited in a range of a smaller axial strain than normal range. The settlement at the surface layer of the ground due to the lightweight embankment was about 1 / 2.75 of the soil embankment and was in agreement with the unit weight ratio (1 / 2.7) of the embankment materials. This indicates the cause and effect of the settlement due to the difference in self weight of the embankments. Also, the difference in settlement between soil and lightweight embankment increased with increasing depth. This shows that the difference in the point at which the settlement is terminated is clear. The ground horizontal displacement under the lightweight embankment was about 15~20% smaller than that of the soil embankment and the depth of occurrence was also 4.5~5.0m shallower in the lightweight embankment.

Earth Pressure on the Underground Box Structure (지중 박스구조물에 작용하는 토압)

  • 이상덕
    • Journal of the Korean Geotechnical Society
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    • v.16 no.1
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    • pp.243-250
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    • 2000
  • The mechanical behavior of the underground box culvert constructed by the open cut method depends mainly on the earth pressure acting on it. In this study, the earth pressure on the underground box culverts constructed by the open cut method during and after the construction sequence was numerically analysed by using FLAC. The results are compared with those of the Marston-Spangler's theory, silo theory, and the model tests. The results showed that the vertical earth pressure on the upper slab of the box structure was not uniform. It was as large as the overburden in the middle part of the slab but was smaller or larger than that at its end part depending on the slope of the excavation, the depth of the cover, and the width of the side refill. The horizontal earth pressure on the side wail was much smaller than the earth pressure at rest and grew nonlinearly with the depth.

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An Experimental Study for Estimation of Compression Settlement on Embankment Material Under Self-weight (성토체 압축침하량 산정에 관한 연구)

  • Kwon, Jeongeun;Noh, Ilkwon;Jung, Juyoung;Im, Jongchul
    • Journal of the Korean GEO-environmental Society
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    • v.10 no.4
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    • pp.33-40
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    • 2009
  • In earthwork projects, the designer considers cut and fill balance for minimizing earthwork which may significantly decrease construction costs. Despite carrying out considerable earthwork design, the decrease in volume of earth occurs in construction sites because of embankment settlement under self-weight, consolidation settlement of soft ground, cavity filling and soil loss due to rainfall-runoff. To reflect the decrease in volume of earth, the specifications for road construction just give shrinkage factors in embankment for soils without consideration of embankment settlement under self-weight. In this study, the computational method is used to estimate the amount of embankment settlement under self-weight developed by Iseda (1972) and Ishii (1976). This research shows that the total compression settlements are between 3 to 10 percent of embankment height according to the property of embankment material and embankment height. As a result, the designer should consider the compression settlement on embankment material under selt-weight.

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Design and Construction of the Green Wall System considering Distribution Effect of Earth Pressure by Soil Nail (쏘일네일의 토압분담효과를 고려한 그린월 시스템의 설계 및 시공)

  • Park, Si-Sam;Cho, Sung-Han
    • Journal of the Korean Geosynthetics Society
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    • v.5 no.3
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    • pp.1-7
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    • 2006
  • The Green Wall system, developed in Austria early 1960, is one of segmental concrete crib type earth retaining wall. Green wall is constructed as procedures that lay the front stretchers, rear stretchers and headers then making a rigid body through harden filled soil of interior cell. Green wall has pro-environmental advantages that able to grow grass in front space of stretchers and decrease cutting ground. In Europe, Green wall used without other reinforcement method. However, green wall used with other reinforcement method like a soil nailing because of environmental problem. This study was performed to introduce the design case by 'Two-Body Translation mechanism' to be able to consider distribution of earth pressure in the soil nailing when designing the green wall using soil nailing system. Also, this study attempts to evaluate the earth pressure change when advanced soil nailing system is constructed using $FLAC^{2D}$ ver. 3.30 program and 'Two-Body Translation mechanism'.

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