• Title/Summary/Keyword: 동상시험

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Development and Verification of High Efficiency Experimental Apparatus to Evaluate Freezing Phenomenon of Soils (고효율 실내 동결실험장비의 개발 및 성능검증)

  • Choi, Chang-Ho
    • Journal of the Korean Geosynthetics Society
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    • v.10 no.4
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    • pp.93-103
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    • 2011
  • In order to design suitable geo-structures in cold region, it is generally required to consider the mechanical properties of permafrost soils. 'Frost heave' as one of the primary phenomenon is considered to be an important factor together with 'adfreeze bond-strength' and 'creep deformation' for structural design process in permafrost area. Therefore, the fundamental study for frost heave has to be preceded for design of geo-structures in cold region. While various experimental apparatuses have been developed, there still exist a certain level of limitation to evaluate the frost-heave characteristics as design parameters. In this paper, a new type of experimental apparatus is proposed to evaluate the engineering characteristics of frost heave in permafrost soils and a set of verification test results is presented. Based on the verification tests, the proposed apparatus is a suitable to obtain frost characteristics of soils.

Application of Paper Sludge Ash-Stabilized Soft Ground for Subgrade Soil (제지애쉬 고화제로 안정처리된 연약지반의 도로노상토 적용에 관한 연구)

  • Shin, Eunchul;Park, Sooyoung
    • Journal of the Korean GEO-environmental Society
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    • v.19 no.6
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    • pp.13-22
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    • 2018
  • The southwestern part of Korean Peninsula, which length is about 13,000 km, is largely formed with soft cohesive soil ground and when it is developed, the low bearing capacity and excessive settlement of soft ground give many problems. In particular, a lot of clayey soil is deserted due to high moisture content and weakness, and areas formed with soft ground. In this study it was performed unconfined compression test, CBR tests, laboratory frost heaving test, and wheel tracking test in order to determine the optimum mixture ratio of paper sludge ash added chemical stabilizer with soft soil for consideration of its frost heaving and strength characteristics. As a results of the above experiments, when the soft soil is mixed with 6% of chemical stabilizer to improve the soft soil for utilizing as a subgrade soil material. It is satisfied the quality standard of fill materials, and the results of this research are expected to be used as an appropriate usage standard for utilization of on-site soil generated.

Analysis of Frozen Reduction Effect and Economic Evaluation of Recycled PET-Soil (재활용 PET 재료를 이용한 골재의 동상저감 효과 분석 및 경제성 평가)

  • Shin, Eun Chul;Shin, Hui Su;Kim, Gi Sung
    • Journal of the Korean Geosynthetics Society
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    • v.13 no.4
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    • pp.153-159
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    • 2014
  • During the winter and spring seasons in Korea, structures such as buried water supply pipelines, roads, railways are frequently damaged due to frost heaving and thawing. Until now, the method of substituting the frost susceptible soil with the gravel or rubbles those are non-frost susceptible materials have been employed in Korea to prevent frost heaving. A series of laboratory soil tests and indoor frozen soil engineering experiments, as well as laboratory frost heaving tests were conducted for seeking the means of utilizing recycled PET bottles as substitute material.

Frost Heave Force of Ground and Countermeasure for Damage of Structures (지반의 동상력과 구조물의 피해대책)

  • Rui, Da-Hu;Teruyuki, Suzuki;Kim, Young-Su
    • Journal of the Korean Geotechnical Society
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    • v.23 no.5
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    • pp.43-51
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    • 2007
  • Frost action may cause extensive damage to building, structures, roads, railways and utility lines in seasonal frost. The research about frost heave of natural ground has been considerably performed. In late years various structures have become complicated with the development of social infrastructure maintenance. Therefore countermeasure to frost heave becomes a matter of great importance from a new viewpoint. This study was aimed at catching natural ground frost heaving force quantitatively. Frost heaving forces on circular steel plates which were set on ground surface were measured in field test. The frost heaving forces arise at freezing front propagates to the structures through frozen soil layer. Besides, a full scale model of multi-anchored retaining wall was installed in field, and the freezing lines, frost heave pressure to act on a wall block, and so on were measured. Finally, the position and shape of frost line were estimated by using numerical simulation and a method to determine replacement range was suggested with soil properties and weather data.

Effect of XPS and Polyethylene Aggregates in Model Tests for Prevention of Frost Heave in Railroad Track (철도에서의 동상방지를 위한 모형시험에서 XPS 및 PE골재의 설치 효과)

  • Kim, Donggwan;Yoon, Yeowon;Kim, Youngchin
    • Journal of the Korean GEO-environmental Society
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    • v.15 no.10
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    • pp.5-13
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    • 2014
  • In this research, in order to study insulation effect of commercial XPS and recycled PE aggregates for prevention of frost heave in the roadbed of railroad track from the freezing temperature, model tests were carried out in the large freezing room. For this, thermal conductivities were measured for various dry densities, water contents, temperatures and mixing ratios of PE aggregates. From the tests, it can be seen that thermal conductivities of roadbed decrease with the increase of the ratio of mixed PE aggregates. However it was sensitive to the changes of temperature and water content due to the amount of water in the voids. From the model test of railroad track, it can be seen that the time to reach $0^{\circ}C$ was longer for XPS than that for the PE aggregates. Also the test shows best insulation effect can be achieved when XPS board was installed above the PE aggregate layer rather than the opposite order.

The Frost Heaving Characteristics of Subgrade Soils Using Laboratory Freezing System (실내동결시스템을 이용한 노상토의 동상 특성)

  • Shin, Eun-Chul;Ryu, Byung-Hyun;Park, Jeong-Jun
    • International Journal of Highway Engineering
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    • v.12 no.2
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    • pp.71-79
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    • 2010
  • The influence of fines of the frost susceptibility of subgrade soils were established by laboratory freezing system test simulating closely the thermal conditions in the field. During the winter season, the climate is heavily influenced by the cold and dry continental high pressure. Because of siberian air mass, the temperature of January is $-6{\sim}-7^{\circ}C$ on average. This chilly weather generate the frost heaving by freezing the moisture of soil and damage potential of the road structure. In the freezing soil, the ice lenses increase the freeze portion of soil by absorbing the ground water with capillary action. However, the capillary characteristics differ from the sort of soil on the state of freezing condition. In the current design codes for anti-freezing layer, the thickness of anti freezing layer is calculated by freezing depth against the temperature condition. Therefore, they have a tendency of over-design and uniform thickness without the considerations of thermal stability, bearing capacity and frost susceptibility of materials. So, it is essential for studying the appropriateness and bearing capacity besides the seasonal and mechanical properties of pavement materials to take a appropriate and reasonable design of the road structure. In this Paper, the evaluation of frost susceptibility was conducted by means of the mechanical property test and laboratory freezing system apparatus. The temperature, heaving amount, heaving pressure and unfrozen water contents of soil samples, the subgrade soils of highway construction site, were measured to determine the frost susceptibility.

Experimental Study of Frost Heaving using Temperature Controlled Triaxial Cell (투명 온도제어형 삼축셀을 이용한 흙의 동상 실내실험)

  • Ryu, Byung-Hyun;Jin, Hyun-Woo;Lee, Jangguen
    • Journal of the Korean GEO-environmental Society
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    • v.17 no.6
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    • pp.23-31
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    • 2016
  • Nowadays abnormal coldness happens frequently in Korea and frost heaving causes unexpected ground deformation which results in severe problems for structures such as roadway, railroad and cutoff slope. 'Frost heave' as one of the primary phenomenon is considered to be an important factor together with 'adfreeze bond-strength' and 'creep deformation' for structural design process in permafrost area. Therefore, the fundamental study for frost heave has to be preceded for design of geo-structures in cold region. While various experimental apparatuses have been developed, there still exist a certain level of limitation to evaluate the frost-heave characteristics as design parameters. There are no standard testing method and criteria for analyzing frost heaving in Korea because temperature controlled testing apparatuses including a freezing chamber are expensive. In this paper, a new standard freezing and thawing testing apparatus is introduced, which simulates various freezing and thawing conditions in a soil specimen by using a temperature controlled triaxial cell. Frost heaving tests were performed to assess the new testing apparatus and experimental procedure to evaluate frost heaving for soils is proposed.

A Study of Frost Penetration Depth and Frost Heaving in Railway Concrete Track (콘크리트 궤도의 동결깊이 및 동상량 측정 연구)

  • Lee, Daeyoung;Kim, Youngchin
    • Journal of the Korean GEO-environmental Society
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    • v.15 no.1
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    • pp.35-41
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    • 2014
  • Many infra suructure such as road, railway, building and utility foundations have been damaged by the repeated freezing and thawing of the soil during winter and spring every year in seasonal frost region. The frost penetration depth is most important factor in the design of structure such as road, railway and building in seasonal frost region. This paper presents the results of calculation of frost penetration depth and frost heaving in concrete track for railway construction. Model concrete track were installed near the railway track in Gangwon, Gyeonggi, Choongbuk province and frost penetration depth were measured using methylene blue frost penetration depth gauge. Model concrete track in Cheolwon, frost heaving of concrete track were also evaluated. The measure of maximum frost penetration depth and frost heaving can be applied to design railway track for cold region in Korea.